Diastereoselective aldol reaction with an acetate enolate: 2,6-Bis(2- isopropylphenyl)-3,5-dimethylphenol as an extremely effective chiral auxiliary

Angewandte Chemie - International Edition

Volumn 37, Issue 24, 1999, Pages 3378-3381

  Saito, Susumu ^a   Hatanaka, Keiko ^a   Kano, Taichi ^a   Yamamoto, Hisashi ^a  

^a NAGOYA UNIVERSITY   (Japan)

Author keywords

Aldol reactions; Asymmetric synthesis; Chiral auxiliaries; Nucleophilic additions

Indexed keywords

PHENOL DERIVATIVE;

ARTICLE; CHEMICAL REACTION; CHEMICAL STRUCTURE; CHIRALITY; POLYMERIZATION; SYNTHESIS;

EID: 0033521679     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/(SICI)1521-3773(19981231)37:24<3378::AID-ANIE3378>3.0.CO;2-L     Document Type: Article

References (41)

1. Examples of syn-selective aldolization with a chiral propionate: a) R. K. Boeckman, Jr., B. T. Connell, J. Am. Chem. Soc. 1995, 117, 12368, and references therein; examples of anti-selective aldolization with a chiral propionate: b) A. Abiko, J.-F. Liu, S. Masamune, J. Am. Chem. Soc. 1997, 119, 2586, and references therein; c) A. K. Ghosh, M. Onishi, J. Am. Chem. Soc. 1996, 118, 2527.
2. Examples of syn-selective aldolization with a chiral propionate: a) R. K. Boeckman, Jr., B. T. Connell, J. Am. Chem. Soc. 1995, 117, 12368, and references therein; examples of anti-selective aldolization with a chiral propionate: b) A. Abiko, J.-F. Liu, S. Masamune, J. Am. Chem. Soc. 1997, 119, 2586, and references therein; c) A. K. Ghosh, M. Onishi, J. Am. Chem. Soc. 1996, 118, 2527.
3. Examples of syn-selective aldolization with a chiral propionate: a) R. K. Boeckman, Jr., B. T. Connell, J. Am. Chem. Soc. 1995, 117, 12368, and references therein; examples of anti-selective aldolization with a chiral propionate: b) A. Abiko, J.-F. Liu, S. Masamune, J. Am. Chem. Soc. 1997, 119, 2586, and references therein; c) A. K. Ghosh, M. Onishi, J. Am. Chem. Soc. 1996, 118, 2527.
4. General reviews of aldol reactions with chiral acetates: a) S. Masamune, W. Choy, J. S. Petersen, L. R. Sita, Angew: Chem. 1985, 97, 1; Angew. Chem. Int. Ed. Engl. 1985, 24, 1; b) M. Braun, Angew. Chem. 1987, 99, 24; Angew. Chem. Int. Ed. Engl. 1987, 26, 24.
5. General reviews of aldol reactions with chiral acetates: a) S. Masamune, W. Choy, J. S. Petersen, L. R. Sita, Angew: Chem. 1985, 97, 1; Angew. Chem. Int. Ed. Engl. 1985, 24, 1; b) M. Braun, Angew. Chem. 1987, 99, 24; Angew. Chem. Int. Ed. Engl. 1987, 26, 24.
6. General reviews of aldol reactions with chiral acetates: a) S. Masamune, W. Choy, J. S. Petersen, L. R. Sita, Angew: Chem. 1985, 97, 1; Angew. Chem. Int. Ed. Engl. 1985, 24, 1; b) M. Braun, Angew. Chem. 1987, 99, 24; Angew. Chem. Int. Ed. Engl. 1987, 26, 24.
7. General reviews of aldol reactions with chiral acetates: a) S. Masamune, W. Choy, J. S. Petersen, L. R. Sita, Angew: Chem. 1985, 97, 1; Angew. Chem. Int. Ed. Engl. 1985, 24, 1; b) M. Braun, Angew. Chem. 1987, 99, 24; Angew. Chem. Int. Ed. Engl. 1987, 26, 24.
8. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
9. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
10. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
11. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
12. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
13. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
14. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
15. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
16. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
17. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
18. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
19. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
20. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
21. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
22. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
23. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
24. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
25. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
26. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
27. Aldol reactions of acetates having chiral auxiliaries: a) M. Braun, R. Devant, Tetrahedron Lett. 1984, 25, 5031; b) G. Helmchen, U. Leikauf, I. Taufer-Knöpfgel, Angew. Chem. 1985, 97, 874; Angew. Chem. Int. Ed. Engl. 1985, 24, 874; c) Y. Nagao, Y. Hagiwara, T. Kumagai, M. Ochiai, T. Inoue, K. Hashimoto, E. Fujita, J. Org. Chem. 1986, 51, 2391; d) R. Devant, U. Mahler, M. Braun, Chem. Ber. 1988, 121, 397, and references therein; e) K. Prasad, K. Ming Chen, O. Repic, G. E. Hardtmann, Tetrahedron: Asymmetry 1990, 1, 703; f) T. Allmendinger, E. Felder, E. Hungerbühler, Tetrahedron Lett. 1990, 31, 7301; g) M. Nerz-Stormes, E. R. Thornton, J. Org. Chem. 1991, 56, 2489; h) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, J. Org. Chem. 1994, 59, 8187; i) T.-H. Yan, A.-W. Hung, H.-C. Lee, C-S. Chang, W-H. Liu, J. Org. Chem. 1995, 60, 3301; j) S. Bond, P. Perlmutter, J. Org. Chem. 1997, 62, 6397; k) L. A. Paquette, D. Zuev, Tetrahedron Lett. 1997, 38, 5115; l) L. A. Paquette, A. Braun, Tetrahedron Lett. 1997, 38, 5119; m) M. Braun, S. Gräf, Org. Synth. Col Vol. 72, 38; for aldol reactions of enolates of acetates having chiral ligands on a metal center: n) S. Masamune, T. Sato, B.-M. Kim, T. A. Wollmann, J. Am. Chem. Soc. 1986, 108, 8279; o) R. O. Duthaler, P. Herold, W. Lottenbach, K. Oertle, M. Riediker, Angew. Chem. 1989, 101, 490; Angew. Chem. Int. Ed. Engl. 1989, 28, 495; p) F. Fringuelli, O. Piermatti, F. Pizzo, J. Org. Chem. 1995, 60, 7006; quite recently, camphor-based methyl ketone was exploited for a stereoselective "acetate" aldol reaction: q) C. Palomo, A. González, J. M. García, C. Landa, M. Oliarbide, S. Rodríguez, A. Linden, Angew. Chem. 1998, 110, 190; Angew. Chem. Int. Ed. 1998, 37, 180.
28. S. Saito, T. Kano, K. Hatanaka, H. Yamamoto, J. Org. Chem. 1997, 62, 5651. A more efficient synthetic route to 3a and 3b will be published in due course.
29. The crude samples of 5-12 and 14-16 were also subjected to HPLC analyses according to the procedures described in reference [8]. The de and ee values obtained were identical to those listed in Tables 1-3.
30. Boron enolates having chiral ligands on the metal center control the stereoselectivity of the reaction; see a) C. Gennari, G. Pain, D. Moresca, J. Org. Chem. 1995, 60, 6248; b) M. T. Reetz, E. Rivadeneria, C. Niemeyer, Tetrahedron Lett. 1990, 31, 3863.
31. Boron enolates having chiral ligands on the metal center control the stereoselectivity of the reaction; see a) C. Gennari, G. Pain, D. Moresca, J. Org. Chem. 1995, 60, 6248; b) M. T. Reetz, E. Rivadeneria, C. Niemeyer, Tetrahedron Lett. 1990, 31, 3863.
32. The aldol reaction of the lithium enolates of acetates with a-substituted propionaldehyde generally leads to a 1:1 mixture of syn and anti products; see C. H. Heathcock in Asymmetric Synthesis, Vol. 3 (Ed.: J. D. Morrison), Academic Press, San Diego, 1984, chap. 2, p. 167, and references therein.
33. 4 to yield a diastereomixture (ca. 1:1) of the starting β-hydroxyesters. The de values of 9 and 12 were determined by chiral GC analyses of the corresponding diol of 9 and the bis(trifluoroacetate) of the corresponding diol of 12 [GC column (Astecs, Ltd.): γ-TA]. For the relative stereochemistry of 14 and 15, see a) T. Matsumoto, I. Tanaka, K. Fukui, Bull. Chem. Soc. Jpn. 1971, 44, 3378; the absolute configurations of 14 and 15 were unambiguously established by comparison with authentic material, which was prepared by treatment of (R,R)-4a with (S)-13a (ca. 80% ee); for 16, see b) Z. Pakulski, A. Zamojski, Tetrahedron 1995, 57, 871; for 8 and 10, see c) Y. Hiraga, W, Shi, D. I. Ito, S. Ohta, T. Suga, J. Chem. Soc. Chem. Commun. 1993, 1367; for 9, see: d) B. E. Rossiter, K. B. Sharpless, J. Org. Chem. 1984, 49, 3707; for 6 and 7, see reference [3 h]. The diol derived from 12 is commercially available.
34. 4 to yield a diastereomixture (ca. 1:1) of the starting β-hydroxyesters. The de values of 9 and 12 were determined by chiral GC analyses of the corresponding diol of 9 and the bis(trifluoroacetate) of the corresponding diol of 12 [GC column (Astecs, Ltd.): γ-TA]. For the relative stereochemistry of 14 and 15, see a) T. Matsumoto, I. Tanaka, K. Fukui, Bull. Chem. Soc. Jpn. 1971, 44, 3378; the absolute configurations of 14 and 15 were unambiguously established by comparison with authentic material, which was prepared by treatment of (R,R)-4a with (S)-13a (ca. 80% ee); for 16, see b) Z. Pakulski, A. Zamojski, Tetrahedron 1995, 57, 871; for 8 and 10, see c) Y. Hiraga, W, Shi, D. I. Ito, S. Ohta, T. Suga, J. Chem. Soc. Chem. Commun. 1993, 1367; for 9, see: d) B. E. Rossiter, K. B. Sharpless, J. Org. Chem. 1984, 49, 3707; for 6 and 7, see reference [3 h]. The diol derived from 12 is commercially available.
35. 4 to yield a diastereomixture (ca. 1:1) of the starting β-hydroxyesters. The de values of 9 and 12 were determined by chiral GC analyses of the corresponding diol of 9 and the bis(trifluoroacetate) of the corresponding diol of 12 [GC column (Astecs, Ltd.): γ-TA]. For the relative stereochemistry of 14 and 15, see a) T. Matsumoto, I. Tanaka, K. Fukui, Bull. Chem. Soc. Jpn. 1971, 44, 3378; the absolute configurations of 14 and 15 were unambiguously established by comparison with authentic material, which was prepared by treatment of (R,R)-4a with (S)-13a (ca. 80% ee); for 16, see b) Z. Pakulski, A. Zamojski, Tetrahedron 1995, 57, 871; for 8 and 10, see c) Y. Hiraga, W, Shi, D. I. Ito, S. Ohta, T. Suga, J. Chem. Soc. Chem. Commun. 1993, 1367; for 9, see: d) B. E. Rossiter, K. B. Sharpless, J. Org. Chem. 1984, 49, 3707; for 6 and 7, see reference [3 h]. The diol derived from 12 is commercially available.
36. 4 to yield a diastereomixture (ca. 1:1) of the starting β-hydroxyesters. The de values of 9 and 12 were determined by chiral GC analyses of the corresponding diol of 9 and the bis(trifluoroacetate) of the corresponding diol of 12 [GC column (Astecs, Ltd.): γ-TA]. For the relative stereochemistry of 14 and 15, see a) T. Matsumoto, I. Tanaka, K. Fukui, Bull. Chem. Soc. Jpn. 1971, 44, 3378; the absolute configurations of 14 and 15 were unambiguously established by comparison with authentic material, which was prepared by treatment of (R,R)-4a with (S)-13a (ca. 80% ee); for 16, see b) Z. Pakulski, A. Zamojski, Tetrahedron 1995, 57, 871; for 8 and 10, see c) Y. Hiraga, W, Shi, D. I. Ito, S. Ohta, T. Suga, J. Chem. Soc. Chem. Commun. 1993, 1367; for 9, see: d) B. E. Rossiter, K. B. Sharpless, J. Org. Chem. 1984, 49, 3707; for 6 and 7, see reference [3 h]. The diol derived from 12 is commercially available.
37. T. Hasegawa, H. Yamamoto, Synlett 1998, 882; see also A. G. Myers, B. H. Yang, H. Chen, L. McKinstry, D. J. Kopecky, J. L. Gleason, J. Am. Chem. Soc. 1997, 119, 6496.
38. T. Hasegawa, H. Yamamoto, Synlett 1998, 882; see also A. G. Myers, B. H. Yang, H. Chen, L. McKinstry, D. J. Kopecky, J. L. Gleason, J. Am. Chem. Soc. 1997, 119, 6496.
39. Kα radiation (λ = 0.71073 Å). The struc ture was solved by direct methods (maXus) and refined with all data by full-matrix least squares on F. All non-hydrogen atoms were refined anisotropically. Hydrogen atoms were added in idealized positions and included in the refinement. Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Center as supplementary publication no. CCDC-102228. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (fax: (+44)1223-336-033; e-mail: deposit@ccdc.cam.ac.uk ).
40. -1. Similarly, it is conceivable that the bulky phenoxy group of the enolate of 4a renders the U form most likely, and gives a twist-boat transition structure: a) C. Gennari, R. Todeschini, M. G. Beretta, G. Favini, C. Scolastico, J. Org. Chem. 1986, 51, 612; b) R. W. Hoffmann, K. Ditrich, S. Froech, Tetrahedron 1985, 41, 5517; see also reference [2b].
41. -1. Similarly, it is conceivable that the bulky phenoxy group of the enolate of 4a renders the U form most likely, and gives a twist-boat transition structure: a) C. Gennari, R. Todeschini, M. G. Beretta, G. Favini, C. Scolastico, J. Org. Chem. 1986, 51, 612; b) R. W. Hoffmann, K. Ditrich, S. Froech, Tetrahedron 1985, 41, 5517; see also reference [2b].