Asymmetric phase-transfer catalysis utilizing chiral quaternary ammonium salts: Asymmetric alkylation of glycine imines

Accounts of Chemical Research

Volumn 37, Issue 8, 2004, Pages 518-525

  Lygo, Barry ^a   Andrews, Benjamin I ^a  

^a UNIVERSITY OF NOTTINGHAM   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

ALPHA AMINO ACID; ANTHRACENE DERIVATIVE; BIPHENYL DERIVATIVE; CINCHONA ALKALOID; GLYCINE; IMINE; N ANTHRACENYLMETHYL DERIVATIVE; QUATERNARY AMMONIUM DERIVATIVE; UNCLASSIFIED DRUG;

ALKYLATION; AMINO ACID SYNTHESIS; ARTICLE; BENZYLATION; CATALYSIS; CHIRALITY; ENANTIOMER; PHASE TRANSITION; REACTION ANALYSIS;

EID: 4143063602     PISSN: 00014842     EISSN: None     Source Type: Journal    
DOI: 10.1021/ar030058t     Document Type: Article

References (82)

1. Halpern, M. E. Phase Transfer Catalysis, Mechanisms and Synthesis; American Chemical Society: Washington, DC, 1997. Handbook of Phase Transfer Catalysis, Sasson, Y., Neumann, R., Eds.; Blackie: London, 1997. Starks, C. M.; Liotta, C. L.; Halpern, M. C. Phase-Transfer Catalysis: Fundamentals, Applications, and Industrial Perspectives; Chapman & Hall: New York, 1994. Phase Transfer Catalysis; Dehmlow, E. V., Dehmlow, S. S., Eds.; VCH: Weinheim, Germany, 1993.
2. Halpern, M. E. Phase Transfer Catalysis, Mechanisms and Synthesis; American Chemical Society: Washington, DC, 1997. Handbook of Phase Transfer Catalysis, Sasson, Y., Neumann, R., Eds.; Blackie: London, 1997. Starks, C. M.; Liotta, C. L.; Halpern, M. C. Phase-Transfer Catalysis: Fundamentals, Applications, and Industrial Perspectives; Chapman & Hall: New York, 1994. Phase Transfer Catalysis; Dehmlow, E. V., Dehmlow, S. S., Eds.; VCH: Weinheim, Germany, 1993.
3. Halpern, M. E. Phase Transfer Catalysis, Mechanisms and Synthesis; American Chemical Society: Washington, DC, 1997. Handbook of Phase Transfer Catalysis, Sasson, Y., Neumann, R., Eds.; Blackie: London, 1997. Starks, C. M.; Liotta, C. L.; Halpern, M. C. Phase-Transfer Catalysis: Fundamentals, Applications, and Industrial Perspectives; Chapman & Hall: New York, 1994. Phase Transfer Catalysis; Dehmlow, E. V., Dehmlow, S. S., Eds.; VCH: Weinheim, Germany, 1993.
4. Halpern, M. E. Phase Transfer Catalysis, Mechanisms and Synthesis; American Chemical Society: Washington, DC, 1997. Handbook of Phase Transfer Catalysis, Sasson, Y., Neumann, R., Eds.; Blackie: London, 1997. Starks, C. M.; Liotta, C. L.; Halpern, M. C. Phase-Transfer Catalysis: Fundamentals, Applications, and Industrial Perspectives; Chapman & Hall: New York, 1994. Phase Transfer Catalysis; Dehmlow, E. V., Dehmlow, S. S., Eds.; VCH: Weinheim, Germany, 1993.
5. Lygo, B. Phase-Transfer Reactions. Rodd's Chemistry of Carbon Compounds, Vol. V. Asymmetric Catalysis; Elsevier Science Ltd.: Oxford, U.K., 2001; pp 101-149.
6. Jones, R. A. Quaternary Ammonium Salts. Their Use in Phase-Transfer Catalysis; Academic Press: London, 2001.
7. See, for example: Yufit, S. S.; Zinovyev, S. S. A comparative kinetic study of nucleophilic substitution under PTC conditions in liquid-liquid and solid-liquid systems. Tetrahedron 1999, 55, 6319-6328. Landini, D.; Maia, A.; Montanari, F. Mechanism of phase-transfer catalysis. J. Chem. Soc., Chem. Commun. 1977, 112-113. Makosza, M.; Bialecka, E. Reactions of organic anions. LXXIII. Alkylation of phenylacetonitrile at the interface with aqueous sodium hydroxide. Tetrahedron Lett. 1977, 18,183-186. Starks, C. M.; Owens, R. M. Phase-transfer catalysis. II. Kinetic details of cyanide displacement on 1-halooctanes. J. Am. Chem. Soc. 1973, 95, 3613-3617.
8. See, for example: Yufit, S. S.; Zinovyev, S. S. A comparative kinetic study of nucleophilic substitution under PTC conditions in liquid-liquid and solid-liquid systems. Tetrahedron 1999, 55, 6319-6328. Landini, D.; Maia, A.; Montanari, F. Mechanism of phase-transfer catalysis. J. Chem. Soc., Chem. Commun. 1977, 112-113. Makosza, M.; Bialecka, E. Reactions of organic anions. LXXIII. Alkylation of phenylacetonitrile at the interface with aqueous sodium hydroxide. Tetrahedron Lett. 1977, 18,183-186. Starks, C. M.; Owens, R. M. Phase-transfer catalysis. II. Kinetic details of cyanide displacement on 1-halooctanes. J. Am. Chem. Soc. 1973, 95, 3613-3617.
9. See, for example: Yufit, S. S.; Zinovyev, S. S. A comparative kinetic study of nucleophilic substitution under PTC conditions in liquid-liquid and solid-liquid systems. Tetrahedron 1999, 55, 6319-6328. Landini, D.; Maia, A.; Montanari, F. Mechanism of phase-transfer catalysis. J. Chem. Soc., Chem. Commun. 1977, 112-113. Makosza, M.; Bialecka, E. Reactions of organic anions. LXXIII. Alkylation of phenylacetonitrile at the interface with aqueous sodium hydroxide. Tetrahedron Lett. 1977, 18,183-186. Starks, C. M.; Owens, R. M. Phase-transfer catalysis. II. Kinetic details of cyanide displacement on 1-halooctanes. J. Am. Chem. Soc. 1973, 95, 3613-3617.
10. See, for example: Yufit, S. S.; Zinovyev, S. S. A comparative kinetic study of nucleophilic substitution under PTC conditions in liquid-liquid and solid-liquid systems. Tetrahedron 1999, 55, 6319-6328. Landini, D.; Maia, A.; Montanari, F. Mechanism of phase-transfer catalysis. J. Chem. Soc., Chem. Commun. 1977, 112-113. Makosza, M.; Bialecka, E. Reactions of organic anions. LXXIII. Alkylation of phenylacetonitrile at the interface with aqueous sodium hydroxide. Tetrahedron Lett. 1977, 18,183-186. Starks, C. M.; Owens, R. M. Phase-transfer catalysis. II. Kinetic details of cyanide displacement on 1-halooctanes. J. Am. Chem. Soc. 1973, 95, 3613-3617.
11. Makosza, M. Phase-transfer catalysis. A general green methodology in organic synthesis. Pure Appl. Chem. 2000, 72, 1399-1403.
12. O'Donnell, M. J. Asymmetric Phase-Transfer Reactions. In Catalytic Asymmetric Synthesis, 2nd ed.; Ojima, I., Ed.; Verlag Chemie: New York, 2000. Shioiri, T. Chiral Phase-Transfer Catalysts. In Handbook of Phase-Transfer Catalysis Sasson, Y., Neumann, R., Eds.; Blackie: London, 1997.
13. O'Donnell, M. J. Asymmetric Phase-Transfer Reactions. In Catalytic Asymmetric Synthesis, 2nd ed.; Ojima, I., Ed.; Verlag Chemie: New York, 2000. Shioiri, T. Chiral Phase-Transfer Catalysts. In Handbook of Phase-Transfer Catalysis Sasson, Y., Neumann, R., Eds.; Blackie: London, 1997.
14. 7N core of the manumycin family: Preparation of (+)-MT 35214 and a formal total synthesis of (-)-alisamycin. Tetrahedron Lett. 1998, 39, 5433-5436. Lygo, B.; Wainwright, P. G. Asymmetric phase-transfer mediated epoxidation of α,β-unsaturated ketones using catalysts derived from cinchona alkaloids. Tetrahedron Lett, 1998, 39, 1599-1602.
15. 7N core of the manumycin family: Preparation of (+)-MT 35214 and a formal total synthesis of (-)-alisamycin. Tetrahedron Lett. 1998, 39, 5433-5436. Lygo, B.; Wainwright, P. G. Asymmetric phase-transfer mediated epoxidation of α,β-unsaturated ketones using catalysts derived from cinchona alkaloids. Tetrahedron Lett, 1998, 39, 1599-1602.
16. 7N core of the manumycin family: Preparation of (+)-MT 35214 and a formal total synthesis of (-)-alisamycin. Tetrahedron Lett. 1998, 39, 5433-5436. Lygo, B.; Wainwright, P. G. Asymmetric phase-transfer mediated epoxidation of α,β-unsaturated ketones using catalysts derived from cinchona alkaloids. Tetrahedron Lett, 1998, 39, 1599-1602.
17. 7N core of the manumycin family: Preparation of (+)-MT 35214 and a formal total synthesis of (-)-alisamycin. Tetrahedron Lett. 1998, 39, 5433-5436. Lygo, B.; Wainwright, P. G. Asymmetric phase-transfer mediated epoxidation of α,β-unsaturated ketones using catalysts derived from cinchona alkaloids. Tetrahedron Lett, 1998, 39, 1599-1602.
18. 7N core of the manumycin family: Preparation of (+)-MT 35214 and a formal total synthesis of (-)-alisamycin. Tetrahedron Lett. 1998, 39, 5433-5436. Lygo, B.; Wainwright, P. G. Asymmetric phase-transfer mediated epoxidation of α,β-unsaturated ketones using catalysts derived from cinchona alkaloids. Tetrahedron Lett, 1998, 39, 1599-1602.
19. 7N core of the manumycin family: Preparation of (+)-MT 35214 and a formal total synthesis of (-)-alisamycin. Tetrahedron Lett. 1998, 39, 5433-5436. Lygo, B.; Wainwright, P. G. Asymmetric phase-transfer mediated epoxidation of α,β-unsaturated ketones using catalysts derived from cinchona alkaloids. Tetrahedron Lett, 1998, 39, 1599-1602.
20. 7N core of the manumycin family: Preparation of (+)-MT 35214 and a formal total synthesis of (-)-alisamycin. Tetrahedron Lett. 1998, 39, 5433-5436. Lygo, B.; Wainwright, P. G. Asymmetric phase-transfer mediated epoxidation of α,β-unsaturated ketones using catalysts derived from cinchona alkaloids. Tetrahedron Lett, 1998, 39, 1599-1602.
21. 7N core of the manumycin family: Preparation of (+)-MT 35214 and a formal total synthesis of (-)-alisamycin. Tetrahedron Lett. 1998, 39, 5433-5436. Lygo, B.; Wainwright, P. G. Asymmetric phase-transfer mediated epoxidation of α,β-unsaturated ketones using catalysts derived from cinchona alkaloids. Tetrahedron Lett, 1998, 39, 1599-1602.
22. O'Donnell, M. J.; Bennett, W. D.; Wu, S. The stareoselective synthesis of α-amino acids by phase-transfer catalysis. J. Am. Chem. Soc. 1989, 111, 2353-2355.
23. O'Donnell, M. J.; Esikova, I. A.; Mi, A.; Shullenberger, D. F.; Wu, S. In Phase-Transfer Catalysis - Mechanisms and Syntheses; Halpern, M. E., Ed.; ACS Symposium Series 659; American Chemical Society: Washington, DC, 1997; pp 124-135. O'Donnell, M. J.; Wu, S.; Huffman, J. C. A new active catalyst species for enantioselective alkylation by phase-transfer catalysis. Tetrahedron 1994, 50, 4507-4518.
24. O'Donnell, M. J.; Esikova, I. A.; Mi, A.; Shullenberger, D. F.; Wu, S. In Phase-Transfer Catalysis - Mechanisms and Syntheses; Halpern, M. E., Ed.; ACS Symposium Series 659; American Chemical Society: Washington, DC, 1997; pp 124-135. O'Donnell, M. J.; Wu, S.; Huffman, J. C. A new active catalyst species for enantioselective alkylation by phase-transfer catalysis. Tetrahedron 1994, 50, 4507-4518.
25. For two recent reviews covering the alkylation of glycine imines, see: Maruoka, K.; Ooi, T. Enantioselective amino acid synthesis by chiral phase-transfer catalysis. Chem. Rev. 2003, 103, 3013-3028. O'Donnell M. J. The preparation of optically active α-amino acids from benzophenone imines of glycine derivatives. Aldrichimica Acta 2001, 34, 3-15.
26. For two recent reviews covering the alkylation of glycine imines, see: Maruoka, K.; Ooi, T. Enantioselective amino acid synthesis by chiral phase-transfer catalysis. Chem. Rev. 2003, 103, 3013-3028. O'Donnell M. J. The preparation of optically active α-amino acids from benzophenone imines of glycine derivatives. Aldrichimica Acta 2001, 34, 3-15.
27. Wainwright, P. G. Ph.D. Thesis, University of Salford, U.K., 1997.
28. Lygo, B.; Crosby, J.; Lowdon, T. R.; Wainwright, P. G. Enantio- and diastereoselective synthesis of all four possible slereoisomers of 2-(phenylhydroxymethyl)quinuclidine. Tetrahedron Lett. 1997, 38, 2343-2346. Lygo, B.; Crosby, J.; Lowdon, T. R.; Wainwright, P. G. Asymmetric approaches to 2-hydroxymethylquinuclidine derivatives. Tetrahedron 1999, 55, 2795-2810.
29. Lygo, B.; Crosby, J.; Lowdon, T. R.; Wainwright, P. G. Enantio- and diastereoselective synthesis of all four possible slereoisomers of 2-(phenylhydroxymethyl)quinuclidine. Tetrahedron Lett. 1997, 38, 2343-2346. Lygo, B.; Crosby, J.; Lowdon, T. R.; Wainwright, P. G. Asymmetric approaches to 2-hydroxymethylquinuclidine derivatives. Tetrahedron 1999, 55, 2795-2810.
30. Lygo, B.; Crosby, J.; Lowdon, T. R.; Wainwright, P. G. Structure-selectivity studies on catalysts for the phase-transfer catalysed asymmetric alkylation of glycine imine esters. Tetrahedron 2001, 57, 2391-2402.
31. For examples of related structure selectivity studies involving Cinchona alkaloid derived phase-transfer catalysts, see: Marsman, B. G. Ph.D. Thesis, University of Gröningen, Netherlands, 1981. Colonna, S.; Re, A.; Wynberg, H. Asymmetric induction in the Michael Reaction by means of chiral phase-transfer catalysts derived from cinchona and ephedra alkaloids. J. Chem. Soc., Perkin Trans. 1 1981, 547-552. Baba, N.; Oda, J.; Kawaguchi, M. Asymmetric epoxidation of cyclic enones under chiral phase-transfer conditions. Agric. Biol. Chem. 1986, 50, 3113-3117. Arai, S.; Hamaguchi, S.; Shioiri, T. Catalytic asymmetric Horner-Wadsworth-Emmons reaction under phase-transfer-catalyzed conditions. Tetrahedron Lett. 1998, 39, 2997-3000. Arai, S.; Nakayama, K.; Ishida, T.; Shioiri, S. Asymmetric cyclopropanation reaction under phase-transfer catalyzed conditions. Tetrahedron Lett. 1999, 40, 4215-4218. Dehmlow, E. V.; Wagner, S.; Müller, A. Enantioselective PTC: Varying the cinchona alkaloid motive. Tetrahedron 1999, 55, 6335-6346.
32. For examples of related structure selectivity studies involving Cinchona alkaloid derived phase-transfer catalysts, see: Marsman, B. G. Ph.D. Thesis, University of Gröningen, Netherlands, 1981. Colonna, S.; Re, A.; Wynberg, H. Asymmetric induction in the Michael Reaction by means of chiral phase-transfer catalysts derived from cinchona and ephedra alkaloids. J. Chem. Soc., Perkin Trans. 1 1981, 547-552. Baba, N.; Oda, J.; Kawaguchi, M. Asymmetric epoxidation of cyclic enones under chiral phase-transfer conditions. Agric. Biol. Chem. 1986, 50, 3113-3117. Arai, S.; Hamaguchi, S.; Shioiri, T. Catalytic asymmetric Horner-Wadsworth-Emmons reaction under phase-transfer-catalyzed conditions. Tetrahedron Lett. 1998, 39, 2997-3000. Arai, S.; Nakayama, K.; Ishida, T.; Shioiri, S. Asymmetric cyclopropanation reaction under phase-transfer catalyzed conditions. Tetrahedron Lett. 1999, 40, 4215-4218. Dehmlow, E. V.; Wagner, S.; Müller, A. Enantioselective PTC: Varying the cinchona alkaloid motive. Tetrahedron 1999, 55, 6335-6346.
33. For examples of related structure selectivity studies involving Cinchona alkaloid derived phase-transfer catalysts, see: Marsman, B. G. Ph.D. Thesis, University of Gröningen, Netherlands, 1981. Colonna, S.; Re, A.; Wynberg, H. Asymmetric induction in the Michael Reaction by means of chiral phase-transfer catalysts derived from cinchona and ephedra alkaloids. J. Chem. Soc., Perkin Trans. 1 1981, 547-552. Baba, N.; Oda, J.; Kawaguchi, M. Asymmetric epoxidation of cyclic enones under chiral phase-transfer conditions. Agric. Biol. Chem. 1986, 50, 3113-3117. Arai, S.; Hamaguchi, S.; Shioiri, T. Catalytic asymmetric Horner-Wadsworth-Emmons reaction under phase-transfer-catalyzed conditions. Tetrahedron Lett. 1998, 39, 2997-3000. Arai, S.; Nakayama, K.; Ishida, T.; Shioiri, S. Asymmetric cyclopropanation reaction under phase-transfer catalyzed conditions. Tetrahedron Lett. 1999, 40, 4215-4218. Dehmlow, E. V.; Wagner, S.; Müller, A. Enantioselective PTC: Varying the cinchona alkaloid motive. Tetrahedron 1999, 55, 6335-6346.
34. For examples of related structure selectivity studies involving Cinchona alkaloid derived phase-transfer catalysts, see: Marsman, B. G. Ph.D. Thesis, University of Gröningen, Netherlands, 1981. Colonna, S.; Re, A.; Wynberg, H. Asymmetric induction in the Michael Reaction by means of chiral phase-transfer catalysts derived from cinchona and ephedra alkaloids. J. Chem. Soc., Perkin Trans. 1 1981, 547-552. Baba, N.; Oda, J.; Kawaguchi, M. Asymmetric epoxidation of cyclic enones under chiral phase-transfer conditions. Agric. Biol. Chem. 1986, 50, 3113-3117. Arai, S.; Hamaguchi, S.; Shioiri, T. Catalytic asymmetric Horner-Wadsworth-Emmons reaction under phase-transfer-catalyzed conditions. Tetrahedron Lett. 1998, 39, 2997-3000. Arai, S.; Nakayama, K.; Ishida, T.; Shioiri, S. Asymmetric cyclopropanation reaction under phase-transfer catalyzed conditions. Tetrahedron Lett. 1999, 40, 4215-4218. Dehmlow, E. V.; Wagner, S.; Müller, A. Enantioselective PTC: Varying the cinchona alkaloid motive. Tetrahedron 1999, 55, 6335-6346.
35. For examples of related structure selectivity studies involving Cinchona alkaloid derived phase-transfer catalysts, see: Marsman, B. G. Ph.D. Thesis, University of Gröningen, Netherlands, 1981. Colonna, S.; Re, A.; Wynberg, H. Asymmetric induction in the Michael Reaction by means of chiral phase-transfer catalysts derived from cinchona and ephedra alkaloids. J. Chem. Soc., Perkin Trans. 1 1981, 547-552. Baba, N.; Oda, J.; Kawaguchi, M. Asymmetric epoxidation of cyclic enones under chiral phase-transfer conditions. Agric. Biol. Chem. 1986, 50, 3113-3117. Arai, S.; Hamaguchi, S.; Shioiri, T. Catalytic asymmetric Horner-Wadsworth-Emmons reaction under phase-transfer-catalyzed conditions. Tetrahedron Lett. 1998, 39, 2997-3000. Arai, S.; Nakayama, K.; Ishida, T.; Shioiri, S. Asymmetric cyclopropanation reaction under phase-transfer catalyzed conditions. Tetrahedron Lett. 1999, 40, 4215-4218. Dehmlow, E. V.; Wagner, S.; Müller, A. Enantioselective PTC: Varying the cinchona alkaloid motive. Tetrahedron 1999, 55, 6335-6346.
36. For examples of related structure selectivity studies involving Cinchona alkaloid derived phase-transfer catalysts, see: Marsman, B. G. Ph.D. Thesis, University of Gröningen, Netherlands, 1981. Colonna, S.; Re, A.; Wynberg, H. Asymmetric induction in the Michael Reaction by means of chiral phase-transfer catalysts derived from cinchona and ephedra alkaloids. J. Chem. Soc., Perkin Trans. 1 1981, 547-552. Baba, N.; Oda, J.; Kawaguchi, M. Asymmetric epoxidation of cyclic enones under chiral phase-transfer conditions. Agric. Biol. Chem. 1986, 50, 3113-3117. Arai, S.; Hamaguchi, S.; Shioiri, T. Catalytic asymmetric Horner-Wadsworth-Emmons reaction under phase-transfer-catalyzed conditions. Tetrahedron Lett. 1998, 39, 2997-3000. Arai, S.; Nakayama, K.; Ishida, T.; Shioiri, S. Asymmetric cyclopropanation reaction under phase-transfer catalyzed conditions. Tetrahedron Lett. 1999, 40, 4215-4218. Dehmlow, E. V.; Wagner, S.; Müller, A. Enantioselective PTC: Varying the cinchona alkaloid motive. Tetrahedron 1999, 55, 6335-6346.
37. Lygo, B.; Wainwright, P. G. A new class of asymmetric phase-transfer catalysts derived from cinchona alkaloids - Application to the enantioselective synthesis of α-amino acids. Tetrahedron Lett. 1997, 38, 8595-8598.
38. Lygo, B.; Crosby, J.; Lowdon, T. R.; Peterson, J. A.; Wainwright, P. G. Studies on the enantioselective synthesis of α-amino acids via asymmetric phase-transfer catalysis. Tetrahedron 2001, 57, 2403-2409.
39. Ion-pair arrangement A has previously been proposed for a closely related phase-transfer catalyst; see ref 22.
40. +-C-H⋯O=C Hydrogen Bonding. J. Am. Chem. Soc. 2002, 124, 7163-7169.
41. +-C-H⋯O=C Hydrogen Bonding. J. Am. Chem. Soc. 2002, 124, 7163-7169.
42. Potential ion-pair arrangements were generated using Monte Carlo search methods in conjunction with the MM2 force field as implemented in Macromodel 7 (Mohamadi, F.; Richards, N. G. J.; Guida, W. C.; Liskamp, R.; Lipton, M.; Caufield, C.; Chang, G.; Hendrickson, T.; Still, W. C. Macromodel - An integrated software system for modelling organic and bioorganic molecules using molecular mechanics. J. Comput. Chem. 1990, 11, 440-467). Ion-pair structures generated in this way were further optimized using semiempirical calculations (PM3) as implemented in Spartan 5 (Wavefunction, Inc., Irvine, CA).
43. See, for example: O'Donnell, M. J.; Delgado, F. Enantiomeric enrichment of α-amino acid derivatives: recrystallization of N-Fmoc α-amino acid tart butyl esters. Tetrahedron 2001, 57, 6641-6650.
44. Lygo, B.; Andrews, B. I.; Crosby, J.; Peterson, J. A. Asymmetric alkylation of glycine imines using in situ generated phase-transfer catalysts. Tetrahedron Lett. 2002, 43, 8015-8018.
45. Corey, E. J.; Xu, F.; Noe, M. C. A Rational approach to catalytic enantioselective enolate alkylation using a structurally rigidified and defined chiral quaternary ammonium salt under phase transfer conditions. J. Am. Chem. Soc. 1997, 119, 12414-12415. Corey, E. J.; Noe, M. C.; Xu, F. Highly enantioselective synthesis of cyclic and functionalized α-amino acids by means of a chiral phase transfer catalyst. Tetrahedron Lett. 1998, 39, 5347-5350.
46. Corey, E. J.; Xu, F.; Noe, M. C. A Rational approach to catalytic enantioselective enolate alkylation using a structurally rigidified and defined chiral quaternary ammonium salt under phase transfer conditions. J. Am. Chem. Soc. 1997, 119, 12414-12415. Corey, E. J.; Noe, M. C.; Xu, F. Highly enantioselective synthesis of cyclic and functionalized α-amino acids by means of a chiral phase transfer catalyst. Tetrahedron Lett. 1998, 39, 5347-5350.
47. O'Donnell, M. J.; Delgado, F.; Hostettler, C.; Schwesinger, R. An efficient homogeneous catalytic enantioselective synthesis of α-amino acid derivatives. Tetrahedron Lett. 1998, 39, 8775-8778. O'Donnell, M. J.; Delgado, F.; Pottorf, R. S. Enantioselective solid-phase synthesis of α-amino acid derivatives. Tetrahedron 1999, 55, 6347-6362.
48. O'Donnell, M. J.; Delgado, F.; Hostettler, C.; Schwesinger, R. An efficient homogeneous catalytic enantioselective synthesis of α-amino acid derivatives. Tetrahedron Lett. 1998, 39, 8775-8778. O'Donnell, M. J.; Delgado, F.; Pottorf, R. S. Enantioselective solid-phase synthesis of α-amino acid derivatives. Tetrahedron 1999, 55, 6347-6362.
49. See, for example: Park, H. G.; Jeong, B. S.; Yoo, M. S.; Lee, J. H.; Park, B. S.; Lee, Y. J.; Kim, M. J.; Jew, S. S. Highly efficient orthofluoro-dimeric cinchona-derived phase-transfer catalysts. Tetrahedron Lett. 2003, 44, 3497-3500. Park, H. G.; Jeong, B. S.; Yoo, M. S.; Lee, J. H.; Park, M. K.; Lee, Y. J.; Kim, M. J.; Jew, S. S. Highly enantioselective and practical cinchona-derived phase-transfer catalysts for the synthesis of α-amino acids. Angew. Chem., Int. Ed. 2002, 41, 3036-3038. Jew, S. S.; Yoo, M. S.; Jeong, B. S.; Park, I. Y.; Park, H. G. An unusual electronic effect of an aromatic-F in phase-transfer catalysts derived from cinchona-alkaloids. Org. Lett. 2002, 4, 4245-4248. Chinchilla, R.; Mazon, P.; Najera, C. New dimeric anthracenyl-derived cinchona quaternary ammonium salts as phase-transfer catalysts for the asymmetric synthesis of α-amino acids. Tetrahedron: Asymmetry 2002, 13, 927-931.
50. See, for example: Park, H. G.; Jeong, B. S.; Yoo, M. S.; Lee, J. H.; Park, B. S.; Lee, Y. J.; Kim, M. J.; Jew, S. S. Highly efficient orthofluoro-dimeric cinchona-derived phase-transfer catalysts. Tetrahedron Lett. 2003, 44, 3497-3500. Park, H. G.; Jeong, B. S.; Yoo, M. S.; Lee, J. H.; Park, M. K.; Lee, Y. J.; Kim, M. J.; Jew, S. S. Highly enantioselective and practical cinchona-derived phase-transfer catalysts for the synthesis of α-amino acids. Angew. Chem., Int. Ed. 2002, 41, 3036-3038. Jew, S. S.; Yoo, M. S.; Jeong, B. S.; Park, I. Y.; Park, H. G. An unusual electronic effect of an aromatic-F in phase-transfer catalysts derived from cinchona-alkaloids. Org. Lett. 2002, 4, 4245-4248. Chinchilla, R.; Mazon, P.; Najera, C. New dimeric anthracenyl-derived cinchona quaternary ammonium salts as phase-transfer catalysts for the asymmetric synthesis of α-amino acids. Tetrahedron: Asymmetry 2002, 13, 927-931.
51. See, for example: Park, H. G.; Jeong, B. S.; Yoo, M. S.; Lee, J. H.; Park, B. S.; Lee, Y. J.; Kim, M. J.; Jew, S. S. Highly efficient orthofluoro-dimeric cinchona-derived phase-transfer catalysts. Tetrahedron Lett. 2003, 44, 3497-3500. Park, H. G.; Jeong, B. S.; Yoo, M. S.; Lee, J. H.; Park, M. K.; Lee, Y. J.; Kim, M. J.; Jew, S. S. Highly enantioselective and practical cinchona-derived phase-transfer catalysts for the synthesis of α-amino acids. Angew. Chem., Int. Ed. 2002, 41, 3036-3038. Jew, S. S.; Yoo, M. S.; Jeong, B. S.; Park, I. Y.; Park, H. G. An unusual electronic effect of an aromatic-F in phase-transfer catalysts derived from cinchona-alkaloids. Org. Lett. 2002, 4, 4245-4248. Chinchilla, R.; Mazon, P.; Najera, C. New dimeric anthracenyl-derived cinchona quaternary ammonium salts as phase-transfer catalysts for the asymmetric synthesis of α-amino acids. Tetrahedron: Asymmetry 2002, 13, 927-931.
52. See, for example: Park, H. G.; Jeong, B. S.; Yoo, M. S.; Lee, J. H.; Park, B. S.; Lee, Y. J.; Kim, M. J.; Jew, S. S. Highly efficient orthofluoro-dimeric cinchona-derived phase-transfer catalysts. Tetrahedron Lett. 2003, 44, 3497-3500. Park, H. G.; Jeong, B. S.; Yoo, M. S.; Lee, J. H.; Park, M. K.; Lee, Y. J.; Kim, M. J.; Jew, S. S. Highly enantioselective and practical cinchona-derived phase-transfer catalysts for the synthesis of α-amino acids. Angew. Chem., Int. Ed. 2002, 41, 3036-3038. Jew, S. S.; Yoo, M. S.; Jeong, B. S.; Park, I. Y.; Park, H. G. An unusual electronic effect of an aromatic-F in phase-transfer catalysts derived from cinchona-alkaloids. Org. Lett. 2002, 4, 4245-4248. Chinchilla, R.; Mazon, P.; Najera, C. New dimeric anthracenyl-derived cinchona quaternary ammonium salts as phase-transfer catalysts for the asymmetric synthesis of α-amino acids. Tetrahedron: Asymmetry 2002, 13, 927-931.
53. Lygo, B.; Allbutt, B.; James, S. R. Identification of a highly effective asymmetric phase-transfer catalyst derived from α-methylnaphthylamine. Tetrahedron Lett. 2003, 44, 5629-5632.
54. 2-symmetric chiral quaternary ammonium bromides as novel chiral phase transfer catalysts: Synthesis and application to practical asymmetric synthesis of α-amino acids. J. Am. Chem. Soc. 2003, 125, 5139-5151. Ooi, T.; Tayama, E.; Maruoka, K. Highly stereoselective N-terminal functionalization of small peptides by chiral phase-transfer catalysis. Angew. Chem., Int. Ed. 2003, 42, 579-582. Ooi, T.; Uematsu, Y.; Kameda, M.; Maruoka, K. Conformationally flexible, chiral quaternary ammonium bromides for asymmetric phase-transfer catalysis. Angew. Chem., Int. Ed. 2002, 41, 1551-1554.
55. 2-symmetric chiral quaternary ammonium bromides as novel chiral phase transfer catalysts: Synthesis and application to practical asymmetric synthesis of α-amino acids. J. Am. Chem. Soc. 2003, 125, 5139-5151. Ooi, T.; Tayama, E.; Maruoka, K. Highly stereoselective N-terminal functionalization of small peptides by chiral phase-transfer catalysis. Angew. Chem., Int. Ed. 2003, 42, 579-582. Ooi, T.; Uematsu, Y.; Kameda, M.; Maruoka, K. Conformationally flexible, chiral quaternary ammonium bromides for asymmetric phase-transfer catalysis. Angew. Chem., Int. Ed. 2002, 41, 1551-1554.
56. 2-symmetric chiral quaternary ammonium bromides as novel chiral phase transfer catalysts: Synthesis and application to practical asymmetric synthesis of α-amino acids. J. Am. Chem. Soc. 2003, 125, 5139-5151. Ooi, T.; Tayama, E.; Maruoka, K. Highly stereoselective N-terminal functionalization of small peptides by chiral phase-transfer catalysis. Angew. Chem., Int. Ed. 2003, 42, 579-582. Ooi, T.; Uematsu, Y.; Kameda, M.; Maruoka, K. Conformationally flexible, chiral quaternary ammonium bromides for asymmetric phase-transfer catalysis. Angew. Chem., Int. Ed. 2002, 41, 1551-1554.
57. Lygo, B.; Allbutt, B. Asymmetric PTC alkylation of glycine imines: Variation of the ester moiety. Synlett 2004, 326-328.
58. Makosza, M.; Krylowa, I. Remarks on the mechanism of phase-transfer catalyzed carbanion generation in two-phase systems. Tetrahedron 1999, 55, 6395-6402. Wu H-S.; Fang, T. R.; Meng, S. S.; Hu, K. H. Equilibrium and extraction of quaternary salt in an organic solvent alkaline solution: effect of NaOH concentration. J. Mol. Catal. A: Chem. 1998, 136, 135-146. Rabinovitz, M.; Cohen, Y.; Halpern, M. Hydroxide ion initiated reactions under phase-transfer catalysis conditions - Mechanisms and implications, Angew. Chem., Int. Ed. Engl. 1986, 25, 960-970. Herriott, A. W.; Picker, D. Phase transfer catalysis. Evaluation of catalysis. J. Am. Chem. Soc. 1975, 97, 2345-2349.
59. Makosza, M.; Krylowa, I. Remarks on the mechanism of phase-transfer catalyzed carbanion generation in two-phase systems. Tetrahedron 1999, 55, 6395-6402. Wu H-S.; Fang, T. R.; Meng, S. S.; Hu, K. H. Equilibrium and extraction of quaternary salt in an organic solvent alkaline solution: effect of NaOH concentration. J. Mol. Catal. A: Chem. 1998, 136, 135-146. Rabinovitz, M.; Cohen, Y.; Halpern, M. Hydroxide ion initiated reactions under phase-transfer catalysis conditions - Mechanisms and implications, Angew. Chem., Int. Ed. Engl. 1986, 25, 960-970. Herriott, A. W.; Picker, D. Phase transfer catalysis. Evaluation of catalysis. J. Am. Chem. Soc. 1975, 97, 2345-2349.
60. Makosza, M.; Krylowa, I. Remarks on the mechanism of phase-transfer catalyzed carbanion generation in two-phase systems. Tetrahedron 1999, 55, 6395-6402. Wu H-S.; Fang, T. R.; Meng, S. S.; Hu, K. H. Equilibrium and extraction of quaternary salt in an organic solvent alkaline solution: effect of NaOH concentration. J. Mol. Catal. A: Chem. 1998, 136, 135-146. Rabinovitz, M.; Cohen, Y.; Halpern, M. Hydroxide ion initiated reactions under phase-transfer catalysis conditions - Mechanisms and implications, Angew. Chem., Int. Ed. Engl. 1986, 25, 960-970. Herriott, A. W.; Picker, D. Phase transfer catalysis. Evaluation of catalysis. J. Am. Chem. Soc. 1975, 97, 2345-2349.
61. Makosza, M.; Krylowa, I. Remarks on the mechanism of phase-transfer catalyzed carbanion generation in two-phase systems. Tetrahedron 1999, 55, 6395-6402. Wu H-S.; Fang, T. R.; Meng, S. S.; Hu, K. H. Equilibrium and extraction of quaternary salt in an organic solvent alkaline solution: effect of NaOH concentration. J. Mol. Catal. A: Chem. 1998, 136, 135-146. Rabinovitz, M.; Cohen, Y.; Halpern, M. Hydroxide ion initiated reactions under phase-transfer catalysis conditions - Mechanisms and implications, Angew. Chem., Int. Ed. Engl. 1986, 25, 960-970. Herriott, A. W.; Picker, D. Phase transfer catalysis. Evaluation of catalysis. J. Am. Chem. Soc. 1975, 97, 2345-2349.
62. Lygo, B.; Andrews, B. I.; Slack, D. Stereoselective approach to C-glycosylasparagines. Tetrahedron Lett. 2003, 44, 9039-9041.
63. Lygo, B.; Humphreys, L. D. Enantioselective synthesis of α-carbon deuterium-labeled L-α-amino acids. Tetrahedron Lett. 2002, 43, 6677-6679.
64. Lygo, B. Enantioselective synthesis of dityrosine and isodityrosine via asymmetric phase-transfer catalysis. Tetrahedron Lett. 1999, 40, 1389-1392.
65. Lygo, B.; Crosby, J.; Peterson, J. A. An enantioselective approach to bis-α-amino acids. Tetrahedron 2001, 57, 6447-6453. Lygo, B.; Crosby J.; Peterson, J. A. Enantioselective synthesis of bis-α-amino acid esters via asymmetric phase-transfer catalysis. Tetrahedron Lett. 1999, 40, 1385-1388.
66. Lygo, B.; Crosby, J.; Peterson, J. A. An enantioselective approach to bis-α-amino acids. Tetrahedron 2001, 57, 6447-6453. Lygo, B.; Crosby J.; Peterson, J. A. Enantioselective synthesis of bis-α-amino acid esters via asymmetric phase-transfer catalysis. Tetrahedron Lett. 1999, 40, 1385-1388.
67. Saba, A. Trans-1,2,3-tris(aroyl)- and trans- 1,2,3-tris(heteroaroyl) cyclopropanes via cyclotrimerization of α-bromoketones in the system potassium carbonate-dimethylformamide. J. Chem. Res. (S) 11990, 288-289.
68. Nitz, M.; Mezo, A. R.; Mayssam, H. A.; Imperiali, B. Enantioselective synthesis and application of the highly fluorescent and environment-sensitive amino acid 6-(2-dimethylaminonaphthoyl) alanine (DANA). Chem. Commun. 2002, 1912-1913.
69. Lygo, B.; Andrews, B. I. Enantioselective synthesis of aroylalanine derivatives. Tetrahedron Lett. 2003, 44, 4499-4502.
70. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
71. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
72. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett.
73. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
74. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
75. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
76. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
77. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
78. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
79. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
80. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
81. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.
82. 2-symmetric chiral pentacyclic guanidine: A phase-transfer catalyst for the asymmetric alkylation of tert-butyl glycinate Schiff base. Angew. Chem., Int. Ed. 2002, 41, 2832-2834. Vyskocil, S.; Meca, L.; Tislerova, I.; Cisarova, I.; Polasek, M.; Harutyunyan, S. R.; Belokon, Y. N.; Stead, R. M. J.; Farrugia, L.; Lockhart, S. C.; Mitchell, W. L.; Kocovsky, P. 2,8′-Disubstituted-1,1′- binaphthyls: A new pattern in chiral ligands. Chem.-Eur. J. 2002, 8, 4633-4648. Mazon, P.; Chinchilla, R.; Najera, C.; Guillena, G.; Kreiter, R.; Gebbink, R. J. M. K.; van Koten, G. Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine. Tetrahedron: Asymmetry 2002, 13, 2181-2185, Shibuguchi, T.; Fukuta, Y.; Akachi, Y.; Sekine, A.; Ohshima, T.; Shibasaki, M. Development of new asymmetric two-center catalysts in phase-transfer reactions. Tetrahedron Lett. 2002, 43, 9539-9543. Arai, S.; Tsuji, R.; Nishida, A. Phase-transfer catalyzed asymmetric Michael reaction using newly prepared chiral quaternary ammonium salts derived from L-tartrate. Tetrahedron Lett, 2002, 43, 9535-9537. Belokon, Y. N.; Kochetkov, K. A.; Churkina, T. D.; Ikonnikov, N. S.; Larionov, O. V.; Harutyunyan, S. R.; Vyskocil, S.; North, M.; Kagan, H. B. Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair. Angew. Chem., Int. Ed. 2001, 40, 1948-1951. Ishikawa, T.; Araki, Y.; Kumamoto, T.; Seki, H.; Fukuda, K.; Isobe, T. Modified guanidines as chiral superbases: application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds. Chem. Commun. 2001, 245-246. Okino, T.; Takemoto, Y. Asymmetric alkylation of tert-butyl glycinate Schiff base with chiral quaternary ammonium salt under micellar conditions. Org. Lett. 2001, 3, 1515-1517. Belokon, Y. N.; North, M.; Churkina, T. D.; Ikonnikov, N. S.; Maleev, V. I. Chiral salen-metal complexes as novel catalysts for the asymmetric synthesis of α-amino acids under phase transfer catalysis conditions. Tetrahedron 2001, 57, 2491-2498. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)glycinate with simple allyl esters under chiral phase transfer conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. O'Donnell, M. J.; Delgado, F.; Dominguez, E.; de Blas, J.; Scott, W. L. Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions. Tetrahedron: Asymmetry 2001, 12, 821-828. Belokon Y. N.; Davies, R. G.; Fuentes, J. A.; North, M.; Persons, T. The influence of imine structure, catalyst structure and reaction conditions on the enantioselectivity of the alkylation of alanine methyl ester imines catalyzed by Cu(ch-salen). Tetrahedron Lett. 2001, 42, 8093-8096.