Asymmetric Organocatalytic Reactions of α,β-Unsaturated: Cyclic Ketones

Symmetry

Volumn 3, Issue 1, 2011, Pages 84-125

  Dalpozzo, Renato ^a   Bartoli, Giuseppe ^b   Bencivenni, Giorgio ^b  

^a UNIVERSITY OF CALABRIA   (Italy)

^b UNIVERSITY OF BOLOGNA   (Italy)

Author keywords

; ; Iminium ion; Michael addition; Organocatalysis; Unsaturated ketones

Indexed keywords

EID: 80054121518     PISSN: None     EISSN: 20738994     Source Type: Journal    
DOI: 10.3390/sym3010084     Document Type: Review

References (104)

1. Michael, A. Ueber die Addition von Natriumacetessig- und Natriummalonsäureäthern zu den Aethern ungesättigter Säuren. J. Prakt. Chem. 1887, 35, 349-356.
2. Berner, O.M.; Tedeschi, L.; Enders, D. Asymmetric Michael Additions to Nitroalkenes. Eur. J. Org. Chem. 2002, 1877-1894.
3. Almasi, D.; Alonso, D.A.; Nájera, C. Organocatalytic Asymmetric Conjugate Additions. Tetrahedron: Asymmetry 2007, 18, 299-365.
4. Tsogoeva, S.B. Recent Advances in Asymmetric Organocatalytic 1,4-Conjugate Additions. Eur. J. Org. Chem. 2007, 1701-1716.
5. Enders, D.; Wang, C.; Bats, J.W. Organocatalytic Asymmetric Domino Reactions: A Cascade Consisting of a Michael Addition and an Aldehyde α-Alkylation. Angew. Chem. Int. Ed. 2008, 47, 7539-7542.
6. Patil, M.P.; Sunoj, R.B. The Role of Noninnocent Solvent Molecules in Organocatalyzed Asymmetric Michael Addition Reactions. Chem. Eur. J. 2008, 14, 10472-10485.
7. Enders, D.; Wang, C.; Liebich, J.X. Organocatalytic Asymmetric Aza-Michael Additions. Chem. Eur. J. 2009, 15, 11058-11076.
8. Janecki, T.; Kedzia, J.; Wasek, T. Michael Additions to Activated Vinylphosphonates. Synthesis 2009, 1227-1254.
9. Li, N.; Xi, G.H.; Wu, Q.H.; Liu, W.H.; Ma, J.J.; Wang, C. Organocatalytic Asymmetric Michael Additions. Chin. J. Org. Chem. 2009, 29, 1018-1038.
10. Bertelsen, S.; Jørgensen, K.A. Organocatalysis-After the Gold Rush. Chem. Soc. Rev. 2009, 38, 2178-2189.
11. Amarante, G.W.; Coelho, F. Organocatalysis Reactions with Chiral Amines. Mechanistic Aspects and Use on Organic Synthesis. Quim. Nova 2009, 32, 469-481.
12. Xu, L.W.; Luo, J.; Lu, Y.X. Asymmetric Catalysis with Chiral Primary Amine-based Organocatalysts. Chem. Commun. 2009, 1807-1821.
13. Palomo, C.; Oiarbide, M.; Lopez, R. Asymmetric Organocatalysis by Chiral Brønsted Bases: Implications and Applications. Chem. Soc. Rev. 2009, 38, 632-653.
14. Tuttle, J.B.; Ouellet, S.G.; MacMillan, D.W.C. Organocatalytic Transfer Hydrogenation of Cyclic Enones. J. Am. Chem. Soc. 2006, 128, 12662-12663.
15. Martin, N.J.A.; List, B. Highly Enantioselective Transfer Hydrogenation of α,β-Unsaturated Ketones. J. Am. Chem. Soc. 2006, 128, 13368-13369.
16. Gutierrez, O.; Iafe, R.G.; Houk, K.N. Origin of Stereoselectivity in the Imidazolidinone-Catalyzed Reductions of Cyclic α,β-Unsaturated Ketones. Org. Lett. 2009, 11, 4298-4301.
17. Yamaguchi, M.; Shiraishi, T.; Hirama, M. A Catalytic Enantioselective Michael Addition of a Simple Malonate to Prochiral α,β-Unsaturated Ketoses and Aldehydes. Angew. Chem. Int. Ed. 1993, 32, 1176-1178.
18. Yamaguchi, M.; Shiraishi, T.; Hirama, M. Asymmetric Michael Addition of Malonate Anions to Prochiral Acceptors Catalyzed by L-Proline Rubidium Salt. J. Org. Chem. 1996, 61, 3520-3530.
19. List, B. Asymmetric Aminocatalysis. Synlett 2001, 1675-1686.
20. Knudsen, K.R.; Mitchell, C.E.T.; Ley, S.V. Asymmetric Organocatalytic Conjugate Addition of Malonates to Enones Using a Proline Tetrazole Catalyst. Chem. Commun. 2006, 66-68.
21. Wascholowski, V.; Knudsen, K.R.; Mitchell, C.E.T.; Ley, S.V. A General Organocatalytic Enantioselective Malonate Addition to α,β-Unsaturated Enones. Chem. Eur. J. 2008, 14, 6155-6165.
22. Kumamoto, T.; Ebine, K.; Endo, M.; Araki, Y.; Fushimi, Y.; Miyamoto, I.; Ishikawa, T.; Isobe, T.; Fukuda, K. Guanidine-catalyzed Asymmetric Addition Reactions: Michael Reaction of Cyclopentenone with Dibenzyl Malonates and Epoxidation of Chalcone. Hetrocycles 2005, 66, 347-359
23. Yang, Y.-Q.; Zhao, G. Organocatalyzed Highly Enantioselective Michael Additions of Malonates to Enones by Using Novel Primary-Secondary Diamine Catalysts. Chem. Eur. J. 2008, 14, 10888-10891.
24. Li, P.; Wen, S.; Yu, F.; Liu, Q.; Li, W.; Wang, Y.; Liang, X.; Ye, J. Enantioselective Organocatalytic Michael Addition of Malonates to α,β-Unsaturated Ketones. Org. Lett. 2009, 11, 753-756.
25. Pansare, S.V.; Lingampally, R. Synthesis and Evaluation of Guanidinyl Pyrrolidines as Bifunctional Catalysts for Enantioselective Conjugate Additions to Cyclic Enones. Org. Biomol. Chem. 2009, 7, 319-324.
26. Riguet, E. Novel Guanidinyl Pyrrolidine Salt-based Bifunctional Organocatalysts: Application in Asymmetric Conjugate Addition of Malonates to Enones. Tetrahedron Lett. 2009, 50, 4283-4285.
27. Yoshida, M.; Narita, M.; Hirama, K.; Hara, S. Asymmetric Michael Addition of Malonates to Enones Catalyzed by a Siloxy Amino Acid Lithium Salt. Tetrahedron Lett. 2009, 50, 7297-7299.
28. Mase, N.; Fukasawa, M.; Kitagawa, N.; Shibagaki, F.; Noshiro, N.; Takabe, K. Organocatalytic Enantioselective Michael Additions of Malonates to 2-Cyclopentenone. Synlett 2010, 2340-2344.
29. Adi Prasetyanto, E.; Lee, S.-C.; Jeong, S.-M.; Park, S.-E. Chiral Enhancement in Diethyl Malonate Addition by Morphosynthesized L-proline Mesoporous Silica. Chem. Commun. 2008, 1995-1997.
30. Dinér, P.; Nielsen, M.; Marigo, M.; Jørgensen, K.A. Enantioselective Organocatalytic Conjugate Addition of N-Heterocycles to α,β-Unsaturated Aldehydes. Angew. Chem. Int. Ed. 2007, 46, 1983-1987.
31. Ye, W.; Jiang, Z.; Zhao, Y.; Goh, S.L.M.; Leow, D.; Soh, Y.-T.; Tan, C.-H. Chiral Bicyclic Guanidine as a Versatile Brønsted Base Catalyst for the Enantioselective Michael Reactions of Dithiomalonates and β-Keto Thioesters. Adv. Synth. Catal. 2007, 349, 2454-2458.
32. Xie, J.-W.; Yue, L.; Chen, W.; Du, W.; Zhu, J.; Deng, J.-G.; Chen, Y.-C. Highly Enantioselective Michael Addition of Cyclic 1,3-Dicarbonyl Compounds to α,β-Unsaturated Ketones. Org. Lett. 2007, 9, 413-415.
33. Wu, F.; Li, H.; Hong, R.; Deng, L. Construction of Quaternary Stereocenters by Efficient and Practical Conjugate Additions to α,β-Unsaturated Ketones with a Chiral Organic Catalyst. Angew. Chem. Int. Ed. 2006, 45, 947-950.
34. Yamaguchi, M.; Shiraishi, T.; Igarashi, Y.; Hirama, M. Catalytic Asymmetric Michael Addition of Nitroalkane to Enone and Enal. Tetrahedron Lett. 1994, 35, 8233-8236.
35. Tsogoeva, S.B.; Jagtap, S.B.; Ardemasova, Z.A.; Kalikhevich, V.N. Trends in Asymmetric Michael Reactions Catalysed by Tripeptides in Combination with an Achiral Additive in Different Solvents. Eur. J. Org. Chem. 2004, 4014-4019.
36. Hanessian, S.; Pham, V. Catalytic Asymmetric Conjugate Addition of Nitroalkanes to Cycloalkenones. Org. Lett. 2000, 2, 2975-2978.
37. Tsogoeva, S.B.; Jagtap, S.B.; Ardemasova, Z.A. 4-trans-Amino-proline Based Di- and Tetrapeptides as Organic Catalysts for Asymmetric C-C Bond Formation Reactions. Tetrahedron: Asymmetry 2006, 17, 989-992.
38. Tsogoeva, S.B.; Jagtap, S.B. Dual Catalyst Control in the Chiral Diamine-Dipeptide-Catalyzed Asymmetric Michael Addition. Synlett 2004, 2624-2626.
39. Mitchell, C.E.T.; Brenner, S.E.; Garcia-Fortanet, J.; Ley, S.V. An Efficient, Asymmetric Organocatalyst-mediated Conjugate Addition of Nitroalkanes to Unsaturated Cyclic and Acyclic Ketones. Org. Biomol. Chem. 2006, 4, 2039-2049.
40. Mitchell, C.E.T.; Brenner, S.E.; Ley, S.V. A Versatile Organocatalyst for the Asymmetric Conjugate Addition of Nitroalkanes to Enones. Chem. Commun. 2005, 5346-5348.
41. Prieto, A.; Halland, N.; Jørgensen, K.A. Novel Imidazolidine-Tetrazole Organocatalyst for Asymmetric Conjugate Addition of Nitroalkanes. Org. Lett. 2005, 7, 3897-3900.
42. Hanessian, S.; Shao, Z.; Warrier, J.S. Optimization of the Catalytic Asymmetric Addition of Nitroalkanes to Cyclic Enones with trans-4,5-Methano-L-proline. Org. Lett. 2006, 8, 4787-4790.
43. Malmgren, M.; Granander, J.; Amedjkouh, M. Asymmetric Conjugate Addition of Nitroalkanes to Enones with a Chiral α-Aminophosphonate Catalyst. Tetrahedron: Asymmetry 2008, 19, 1934-1940.
44. Li, P.; Wang, Y.; Liang, X.; Ye, J. Asymmetric multifunctional organocatalytic Michael addition of nitroalkanes to α,β-unsaturated ketones. Chem. Commun. 2008, 3302-3304.
45. Liu, C.; Lu, Y. Primary Amine/(+)-CSA Salt-Promoted Organocatalytic Conjugate Addition of Nitro Esters to Enones. Org. Lett. 2010, 12, 2278-2281.
46. Hanessian, S.; Govindan, S.; Warrier, J.S. Probing the "Additive Effect" in the Proline and Proline Hydroxamic Acid Catalyzed Asymmetric Addition of Nitroalkanes to Cyclic Enones. Chirality 2005, 17, 540-543.
47. Ooi, T.; Doda, K.; Takada, S.; Maruoka, K. Asymmetric Michael Addition of Silyl Nitronates to Cyclic α,β-Unsaturated Ketones Catalyzed by Chiral Quaternary Ammonium Bifluorides:Isolation and Selective Functionalization of Enol Silyl Ethers of Optically Active γ-Nitro Ketones. Tetrahedron Lett. 2006, 47, 145-148.
48. Ooi, T.; Takada, S.; Fujioka, S.; Maruoka, K. N-Spiro Chiral Quaternary Ammonium Bromide Catalyzed Diastereo- and Enantioselective Conjugate Addition of Nitroalkanes to Cyclic α,β-Unsaturated Ketones under Phase-Transfer Conditions. Org. Lett. 2005, 7, 5143-5146.
49. Piovesana, S.; Schietroma, D.M.S.; Tulli, L.G.; Monaco, M.R.; Bella, M. Unsaturated β-Ketoesters as Versatile Electrophiles in Organocatalysis. Chem. Commun. 2010, 46, 5160-5162.
50. Arai, S.; Nakayama, K.; Ishida, T.; Shioiri, T. Asymmetric Cyclopropanation Reaction under Phase-transfer Catalyzed Conditions. Tetrahedron Lett. 1999, 40, 4215-4218.
51. Wascholowski, V.; Hansen, H.M.; Longbottom, D.A.; Ley, S.V. A General Organocatalytic Enantioselective Nitrocyclopropanation Reaction. Synthesis 2008, 1269-1275.
52. Dong, L.-T.; Du, Q.-S.; Lou, C.-L.; Zhang, J.-M.; Lu, R.-J.; Yan, M. Asymmetric Synthesis of Nitrocyclopropanes Catalyzed by Chiral Primary Amines. Synlett 2010, 266-270.
53. Du, Q.-S.; Dong, L.-T.; Wang, J.-J.; Lu, R.-J.; Yan, M. Asymmetric Conjugate Addition of Bromonitromethane to Cyclic Enones Catalyzed by Chiral Monosulfonated Diamines. Arkivoc 2009, XIV, 191-199.
54. Hansen, H.M.; Longbottom, D.A.; Ley, S.V. A New Asymmetric Organocatalytic Nitrocyclopropanation Reaction. Chem. Commun. 2006, 4838-4840.
55. Lv, J.; Zhang, J.; Lin, Z.; Wang, Y. Enantioselective Synthesis of Functionalized Nitrocyclopropanes by Organocatalytic Conjugate Addition of Bromonitroalkanes to α,β-Unsaturated Enones. Chem. Eur. J. 2009, 15, 972-979.
56. Ceccarelli, R.; Insogna, S.; Bella, M. Organocatalytic Regioselective Michael Additions of Cyclic Enones via Asymmetric Phase Transfer Catalysis. Org. Biomol. Chem. 2006, 4, 4281-4284.
57. Paixão, M.W.; Holub, N.; Vila, C.; Nielsen, M.; Jørgensen, K.A. Trends in Organocatalytic Conjugate Addition to Enones: An Efficient Approach to Optically Active Alkynyl, Alkenyl, and Ketone Products. Angew. Chem. Int. Ed. 2009, 48, 7338-7342.
58. Holub, N.; Jiang, H.; Paixão, M.W.; Tiberi, C.; Jørgensen, K.A. An Unexpected Michael-Aldol- Smiles Rearrangement Sequence for the Synthesis of Versatile Optically Active Bicyclic Structures by Using Asymmetric Organocatalysis. Chem. Eur. J. 2010, 16, 4337-4346.
59. Cid, M.B.; Lopez-Cantarero, J.; Duce, S.; Ruano, J.L.G. Enantioselective Organocatalytic Approach to the Synthesis of α,α-Disubstituted Cyanosulfones. J. Org. Chem. 2009, 74, 431-434.
60. Bartoli, G.; Bencivenni, G.; Dalpozzo, R. Organocatalytic Strategies for the Asymmetric Functionalization of Indoles. Chem. Soc. Rev. 2010, 39, 4449-4465.
61. Bandini, M.; Eichholzer, A. Catalytic Functionalization of Indoles in a New Dimension. Angew. Chem. Int. Ed. 2009, 48, 9608-9644.
62. Tang, H.-Y.; Lu, A.-D.; Zhou, Z.-H.; Zhao, G.-F.; He, L.-N.; Tang, C.-C. Chiral Phosphoric Acid Catalyzed Asymmetric Friedel-Crafts Alkylation of Indoles with Simple α,β-Unsaturated Aromatic Ketones. Eur. J. Org. Chem. 2008, 1406-1410.
63. Bartoli, G.; Bosco, M.; Carlone, A.; Pesciaioli, F.; Sambri, L.; Melchiorre, P. Organocatalytic Asymmetric Friedel-Crafts Alkylation of Indoles with Simple α,β-Unsaturated Ketones. Org. Lett. 2007, 9, 1403-1405.
64. Pesciaioli, F.; Tian, X.; Bencivenni, G.; Bartoli, G.; Melchiorre, P. Organocatalytic Asymmetric Conjugate Additions of Oxindoles and Benzofuranones to Cyclic Enones. Synlett 2010, 1704-1708.
65. Helder, R.; Arends, R.; Bolt, W.; Hiemstra, H.; Wynberg, H. Alkaloid Catalyzed Asymmetric Synthesis III the Addition of Mercaptans to 2-Cyclohexene-1-one; Determination of Enantiomeric Excess Using 13C NMR. Tetrahedron Lett. 1977, 18, 2181-2182.
66. Hiemstra, H.; Wynberg, H. Addition of Aromatic Thiols to Conjugated Cycloalkenones, Catalyzed by Chiral β-Hydroxy Amines. A Mechanistic Study of Homogeneous Catalytic Asymmetric Synthesis. J. Am. Chem. Soc. 1981, 103, 417-430.
67. Mukaiyama, T.; Ikegawa, A.; Suzuki, K. Highly Enantioselective Michael Addition of Thiols to 2-Cyclohexenone by Using (2S,4S)-2-(Anilinomethyl)-1-ethyl-4-hydroxypyrrolidine as a Chiral Catalyst. Chem. Lett. 1981, 10, 165-168.
68. Suzuki, K.; Ikegawa, A.; Mukaiyama, T. The Enantioselective Michael Addition of Thiols to Cycloalkenones by Using (2S, 4S)-2-Anilinomethyl-1-ethyl-4-hydroxypyrrolidine as Chiral Catalyst. Bull. Chem. Soc. J. 1982, 55, 3277-3282.
69. Sera, A.; Takagi, K.; Katayama, H.; Yamada, H.; Matsumoto, K. High-pressure Asymmetric Michael Additions of Thiols, Nitromethane, and Methyl Oxoindancarboxylate to Enones. J. Org. Chem. 1988, 53, 1157-1161.
70. McDaid, P.; Chen, Y.; Deng, L. A Highly Enantioselective and General Conjugate Addition of Thiols to Cyclic Enones with an Organic Catalyst. Angew. Chem. Int. Ed. 2002, 41, 338-340.
71. Li, B.-J.; Jiang, L.; Liu, M.; Chen, Y.-C.; Ding, L.-S.; Wu, Y. Asymmetric Michael Addition of Arylthiols to α,β-Unsaturated Carbonyl Compounds Catalyzed by Bifunctional Organocatalysts. Synlett 2005, 603-606.
72. Kumar, A.; Akanksha Amino Acid Catalyzed Thio-Michael Addition Reactions. Tetrahedron 2007, 63, 11086-11092.
73. Shirakawa, S.; Moriyama, A.; Shimizu, S. Design of a Novel Inherently Chiral Calix[4]arene for Chiral Molecular Recognition. Org. Lett. 2007, 9, 3117-3119.
74. Shirakawa, S.; Kimura, T.; Murata, S.-I.; Shimizu, S. Synthesis and Resolution of a Multifunctional Inherently Chiral Calix[4]arene with an ABCD Substitution Pattern at the Wide Rim: The Effect of a Multifunctional Structure in the Organocatalyst on Enantioselectivity in Asymmetric Reactions. J. Org. Chem. 2009, 74, 1288-1296.
75. Rana, N.K.; Selvakumar, S.; Singh, V.K. Highly Enantioselective Organocatalytic Sulfa-Michael Addition to α,β-Unsaturated Ketones. J. Org. Chem. 2010, 75, 2089-2091.
76. Yoshida, M.; Ohno, Y.; Hara, S. Organocatalytic Asymmetric Thio-Michael Addition of Arylmethyl Mercaptans to Cyclic Enones by a Primary Amino Acid. Tetrahedron Lett. 2010, 51, 5134-5136.
77. Meciarova, M.; Toma, S.; Kotrusz, P. Michael Addition of Thiols to α-Enones in Ionic Liquids with and without Organocatalysts. Org. Biomol. Chem. 2006, 4, 1420-1424.
78. Gawronski, J.; Gawronska, K.; Wynberg, H. Alkaloid-catalysed Asymmetric Addition of Thiocarboxylic S-Acids to Cyclohex-2-en-1-ones. Absolute Configuration of the Adducts by O,S-Dibenzoate Cotton Effect. J. Chem. Soc., Chem. Commun. 1981, 307-308.
79. Rios, R.; Sundén, H.; Ibrahem, I.; Zhao, G.-L.; Córdova, A. A One-pot Organocatalytic Asymmetric Entry to Tetrahydrothioxanthenones. Tetrahedron Lett. 2006, 47, 8679-8682.
80. Rios, R.; Sundén, H.; Ibrahem, I.; Córdova, A. A Simple and Concise Catalytic Asymmetric Entry to Tetrahydroxanthenones. Tetrahedron Lett. 2007, 48, 2181-2184.
81. Xia, A.-B.; Xu, D.-Q.; Luo, S.-P.; Jiang, J.-R.; Tang, J.; Wang, Y.-F.; Xu, Z.-Y. Dual Organocatalytic Ion-Pair Assemblies: A Highly Efficient Approach for the Enantioselective Oxa-Michael-Mannich Reaction of Salicylic Aldehydes with Cyclohexenones. Chem. Eur. J. 2010, 16, 801-804.
82. Wang, X.; Reisinger, C.M.; List, B. Catalytic Asymmetric Epoxidation of Cyclic Enones. J. Am. Chem. Soc. 2008, 130, 6070-6071.
83. Pluim, H.; Wynberg, H. Alkaloid Catalysed Asymmetric Synthesis. The Addition of Selenophenols to 2-Cyclohexen-1-ones and Conversion to Optically Active Allylic Alcohols. Tetrahedron Lett. 1979, 20, 1251-1254.
84. Perdicchia, D.; Jørgensen, K.A. Asymmetric Aza-Michael Reactions Catalyzed by Cinchona Alkaloids. J. Org. Chem. 2007, 72, 3565-3568.
85. Pesciaioli, F.; de Vincentiis, F.; Galzerano, P.; Bencivenni, G.; Bartoli, G.; Mazzanti, A.; Melchiorre, P. Organocatalytic Asymmetric Aziridination of Enones. Angew. Chem. Int. Ed. 2008, 47, 8703-8706.
86. de Vincentiis, F.; Bencivenni, G.; Pesciaioli, F.; Mazzanti, A.; Bartoli, G.; Galzerano, P.; Melchiorre, P. Asymmetric Catalytic Aziridination of Cyclic Enones. Chem. Asian J. 2010, 5, 1652-1656.
87. Northrup, A.B.; MacMillan, D.W.C. The First General Enantioselective Catalytic Diels-Alder Reaction with Simple α,β-Unsaturated Ketones. J. Am. Chem. Soc. 2002, 124, 2458-2460.
88. Chen, W.; Du, W.; Duan, Y.-Z.; Wu, Y.; Yang, S.-Y.; Chen, Y.-C. Enantioselective 1,3-Dipolar Cycloaddition of Cyclic Enones Catalyzed by Multifunctional Primary Amines: Beneficial Effects of Hydrogen Bonding. Angew. Chem. Int. Ed. 2007, 46, 7667-7670.
89. Sundén, H.; Rios, R.; Xu, Y.; Eriksson, L.; Córdova, A. Direct Enantioselective Synthesis of Bicyclic Diels-Alder Products. Adv. Synth. Catal. 2007, 349, 2549-2555.
90. Xu, D.-Q.; Xia, A.-B.; Luo, S.-P.; Tang, J.; Zhang, S.; Jiang, J.-R.; Xu, Z.-Y. In Situ Enamine Activation in Aqueous Salt Solutions: Highly Efficient Asymmetric Organocatalytic Diels-Alder Reaction of Cyclohexenones with Nitroolefins. Angew. Chem. Int. Ed. 2009, 48, 3821-3824.
91. Bella, M.; Schietroma, D.M.S.; Cusella, P.P.; Gasperi, T.; Visca, V. Synergic Asymmetric Organocatalysis (SAOc) of Cinchona alkaloids and Secondary Amines in the Synthesis of Bicyclo[2.2.2]octan-2-ones. Chem. Commun. 2009, 597-599.
92. Liu, H.; Cun, L.-F.; Mi, A.-Q.; Jiang, Y.-Z.; Gong, L.-Z. Enantioselective Direct Aza Hetero-Diels-Alder Reaction Catalyzed by Chiral Brønsted Acids. Org. Lett. 2006, 8, 6023-6026.
93. Rueping, M.; Azap, C. Cooperative Coexistence: Effective Interplay of Two Brønsted Acids in the Asymmetric Synthesis of Isoquinuclidines. Angew. Chem. Int. Ed. 2006, 45, 7832-7835
94. Sundén, H.; Ibrahem, I.; Eriksson, L.; Córdova, A. Direct Catalytic Enantioselective Aza-Diels- Alder Reactions. Angew. Chem. Int. Ed. 2005, 44, 4877-4880.
95. Yang, H.; Carter, R.G. Asymmetric Construction of Nitrogen-Containing [2.2.2] Bicyclic Scaffolds Using N-(p-Dodecylphenylsulfonyl)-2-pyrrolidinecarboxamide. J. Org. Chem. 2009, 74, 5151-5156.
96. Momiyama, N.; Yamamoto, H. Brønsted Acid Catalysis of Achiral Enamine for Regio- and Enantioselective Nitroso Aldol Synthesis. J. Am. Chem. Soc. 2005, 127, 1080-1081.
97. Momiyama, N.; Yamamoto, Y.; Yamamoto, H. Diastereo- and Enantioselective Synthesis of Nitroso Diels-Alder-Type Bicycloketones Using Dienamine: Mechanistic Insight into Sequential Nitroso Aldol/Michael Reaction and Application for Optically Pure 1-Amino-3,4-diol Synthesis. J. Am. Chem. Soc. 2007, 129, 1190-1195.
98. Yamamoto, Y.; Momiyama, N.; Yamamoto, H. Enantioselective Tandem O-Nitroso Aldol/Michael Reaction. J. Am. Chem. Soc. 2004, 126, 5962-5963.
99. Hayashi, Y.; Gotoh, H.; Tamura, T.; Yamaguchi, H.; Masui, R.; Shoji, M. Cysteine-Derived Organocatalyst in a Highly Enantioselective Intramolecular Michael Reaction. J. Am. Chem. Soc. 2005, 127, 16028-16029.
100. Liu, Q.; Rovis, T. Asymmetric Synthesis of Hydrobenzofuranones via Desymmetrization of Cyclohexadienones Using the Intramolecular Stetter Reaction. J. Am. Chem. Soc. 2006, 128, 2552-2553.
101. Vo, N.T.; Pace, R.D.M.; O'Har, F.; Gaunt, M.J. An Enantioselective Organocatalytic Oxidative Dearomatization Strategy. J. Am. Chem. Soc. 2007, 130, 404-405.
102. Gu, Q.; Rong, Z.-Q.; Zheng, C.; You, S.-L. Desymmetrization of Cyclohexadienones via Brønsted Acid-Catalyzed Enantioselective Oxo-Michael Reaction. J. Am. Chem. Soc. 2010, 132, 4056-4057.
103. Alemán, J.; Cabrera, S.; Maerten, E.; Overgaard, J.; Jørgensen, K.A. Asymmetric Organocatalytic α-Arylation of Aldehydes. Angew. Chem. Int. Ed. 2007, 46, 5520-5523.
104. Alemán, J.; Richter, B.; Jørgensen, K.A. Organocatalytic Highly Enantioselective α-Arylation of β-Ketoesters. Angew. Chem. Int. Ed. 2007, 46, 5515-5519.