A Highly Enantiomerically Enriched α-Thiobenzyl Derivative with Unusual Configurational Stability

Angewandte Chemie (International Edition in English)

Volumn 36, Issue 24, 1997, Pages 2784-2786

  Hoppe, Dieter ^a   Kaiser, Bernd ^a   Stratmann, Oliver ^a   Fröhlich, Roland ^a  

^a UNIVERSITY OF MÜNSTER   (Germany)

Author keywords

Carbanions; Chirality; Configuration inversion; Ion pairs; Lithium

Indexed keywords

EID: 0032491848     PISSN: 05700833     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.199727841     Document Type: Article

References (61)

1. Reviews: a) V. Aggarwal, Angew. Chem. 1994, 106, 185-187; Angew. Chem. Int. Ed. Engl. 1994, 33, 175-177; b) P. Beak, A. Basu, D. J. Gallagher, Y. S. Park, S. Thayumanavan, Acc. Chem. Res. 1996, 29, 552-560; c) D. Hoppe, T. Hense, Angew. Chem 1997, 109, 2376-2410; Angew. Chem. Int. Ed. Engl. 1997, 36, 2282-2316.
2. Reviews: a) V. Aggarwal, Angew. Chem. 1994, 106, 185-187; Angew. Chem. Int. Ed. Engl. 1994, 33, 175-177; b) P. Beak, A. Basu, D. J. Gallagher, Y. S. Park, S. Thayumanavan, Acc. Chem. Res. 1996, 29, 552-560; c) D. Hoppe, T. Hense, Angew. Chem 1997, 109, 2376-2410; Angew. Chem. Int. Ed. Engl. 1997, 36, 2282-2316.
3. Reviews: a) V. Aggarwal, Angew. Chem. 1994, 106, 185-187; Angew. Chem. Int. Ed. Engl. 1994, 33, 175-177; b) P. Beak, A. Basu, D. J. Gallagher, Y. S. Park, S. Thayumanavan, Acc. Chem. Res. 1996, 29, 552-560; c) D. Hoppe, T. Hense, Angew. Chem 1997, 109, 2376-2410; Angew. Chem. Int. Ed. Engl. 1997, 36, 2282-2316.
4. Reviews: a) V. Aggarwal, Angew. Chem. 1994, 106, 185-187; Angew. Chem. Int. Ed. Engl. 1994, 33, 175-177; b) P. Beak, A. Basu, D. J. Gallagher, Y. S. Park, S. Thayumanavan, Acc. Chem. Res. 1996, 29, 552-560; c) D. Hoppe, T. Hense, Angew. Chem 1997, 109, 2376-2410; Angew. Chem. Int. Ed. Engl. 1997, 36, 2282-2316.
5. Reviews: a) V. Aggarwal, Angew. Chem. 1994, 106, 185-187; Angew. Chem. Int. Ed. Engl. 1994, 33, 175-177; b) P. Beak, A. Basu, D. J. Gallagher, Y. S. Park, S. Thayumanavan, Acc. Chem. Res. 1996, 29, 552-560; c) D. Hoppe, T. Hense, Angew. Chem 1997, 109, 2376-2410; Angew. Chem. Int. Ed. Engl. 1997, 36, 2282-2316.
6. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
7. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
8. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
9. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
10. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
11. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
12. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
13. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
14. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
15. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
16. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
17. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
18. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
19. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
20. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
21. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
22. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
23. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
24. Examples of the preparation of enantiomerically enriched, configurationally stable and not mesomerically stabilized α-oxycarbanion equivalents: a) W. C. Still, C. Sreekumar, J. Am. Chem. Soc. 1980, 102, 1201-1202; b) P.-C.-M. Chan, J. M. Chong, J. Org. Chem. 1988, 53, 5584-5586; c) J. A. Marshall, W. Y. Gung. Tetrahedron 1989, 45, 1043-1052; d) D. S. Matteson, P. B. Tripathy, A. Sarkar, K. M. Sadhu, J. Am. Chem. Soc. 1989, 111, 4399-4402; e) D. Hoppe, F. Hintze, P. Tebben, Angew. Chem. 1990, 102, 1457-1459; Angew. Chem. Int. Ed. Engl. 1990, 29, 1424-1425; f) K. Tomooka, T. Igarashi, T. Nakai, Tetrahedron 1994, 50, 5927-5932; g) L. Colombo, M. Di Giacomo, G. Brusotti, G. Delogu, Tetrahedron Lett. 1994, 35, 2063-2066; h) M. Hoffmann, H. Kessler, ibid. 1995, 36, 6067-6070; i) S. D. Rychnovsky, Chem. Rev. 1995, 93, 2021-2040; k) N. S. Mani, C. A. Townsend, J. Org. Chem. 1997, 62, 636-640; resonance-stabilized α-oxycarbanion equivalents: l) O. Zschage, J.-R. Schwark, D. Hoppe, Angew. Chem. 1990, 102, 336-337; Angew. Chem. Int. Ed. Engl. 1990, 29, 296-298; m) O. Zschage, J.-R. Schwark, T. Krämer, D. Hoppe, Tetrahedron 1992, 48, 8377-8388; n) D. Hoppe, A. Carstens, T. Kramer, Angew. Chem. 1990, 102, 1455-1456; Angew. Chem. Int. Ed. Engl. 1990, 29, 1422-1424; o) A. Carstens, D. Hoppe, Tetrahedron 1994, 50, 6097-6108; p) C. Derwing, D. Hoppe, Synthesis 1996, 149-154; q) F. Hammerschmidt, A. Hanninger, Chem. Ber. 1995, 128, 1069-1077.
25. Examples of α-amino-substituted carbanion equivalents: a) S. T. Kerrick, P. Beak, J. Am. Chem. Soc. 1991, 113, 9708-9710; b) R. E. Gawley, Q. Zhang, Tetrahedron 1994, 50, 6077-6088; c) A. F. Burchat, J. M. Chong, S. B. Park, Tetrahedron Lett. 1993, 34, 51-54; d) W. H. Pearson, A. C. Lindbeck, J. W. Kampf, J. Am. Chem. Soc. 1993, 115, 2622-2636; e) T. R. Elworthy, A. I. Meyers, Tetrahedron 1994, 50, 6089-6096; f) M. E. Kopach, A. I. Meyers, J. Org. Chem. 1996, 61, 6764-6765; g) I. Coldham, R. Hufton, D. J. Snowden, J. Am. Chem. Soc. 1996, 118, 5322-5323; h) G. A. Weisenburger, P. Beak, ibid. 1996, 118, 12218-12219.
26. Examples of α-amino-substituted carbanion equivalents: a) S. T. Kerrick, P. Beak, J. Am. Chem. Soc. 1991, 113, 9708-9710; b) R. E. Gawley, Q. Zhang, Tetrahedron 1994, 50, 6077-6088; c) A. F. Burchat, J. M. Chong, S. B. Park, Tetrahedron Lett. 1993, 34, 51-54; d) W. H. Pearson, A. C. Lindbeck, J. W. Kampf, J. Am. Chem. Soc. 1993, 115, 2622-2636; e) T. R. Elworthy, A. I. Meyers, Tetrahedron 1994, 50, 6089-6096; f) M. E. Kopach, A. I. Meyers, J. Org. Chem. 1996, 61, 6764-6765; g) I. Coldham, R. Hufton, D. J. Snowden, J. Am. Chem. Soc. 1996, 118, 5322-5323; h) G. A. Weisenburger, P. Beak, ibid. 1996, 118, 12218-12219.
27. Examples of α-amino-substituted carbanion equivalents: a) S. T. Kerrick, P. Beak, J. Am. Chem. Soc. 1991, 113, 9708-9710; b) R. E. Gawley, Q. Zhang, Tetrahedron 1994, 50, 6077-6088; c) A. F. Burchat, J. M. Chong, S. B. Park, Tetrahedron Lett. 1993, 34, 51-54; d) W. H. Pearson, A. C. Lindbeck, J. W. Kampf, J. Am. Chem. Soc. 1993, 115, 2622-2636; e) T. R. Elworthy, A. I. Meyers, Tetrahedron 1994, 50, 6089-6096; f) M. E. Kopach, A. I. Meyers, J. Org. Chem. 1996, 61, 6764-6765; g) I. Coldham, R. Hufton, D. J. Snowden, J. Am. Chem. Soc. 1996, 118, 5322-5323; h) G. A. Weisenburger, P. Beak, ibid. 1996, 118, 12218-12219.
28. Examples of α-amino-substituted carbanion equivalents: a) S. T. Kerrick, P. Beak, J. Am. Chem. Soc. 1991, 113, 9708-9710; b) R. E. Gawley, Q. Zhang, Tetrahedron 1994, 50, 6077-6088; c) A. F. Burchat, J. M. Chong, S. B. Park, Tetrahedron Lett. 1993, 34, 51-54; d) W. H. Pearson, A. C. Lindbeck, J. W. Kampf, J. Am. Chem. Soc. 1993, 115, 2622-2636; e) T. R. Elworthy, A. I. Meyers, Tetrahedron 1994, 50, 6089-6096; f) M. E. Kopach, A. I. Meyers, J. Org. Chem. 1996, 61, 6764-6765; g) I. Coldham, R. Hufton, D. J. Snowden, J. Am. Chem. Soc. 1996, 118, 5322-5323; h) G. A. Weisenburger, P. Beak, ibid. 1996, 118, 12218-12219.
29. Examples of α-amino-substituted carbanion equivalents: a) S. T. Kerrick, P. Beak, J. Am. Chem. Soc. 1991, 113, 9708-9710; b) R. E. Gawley, Q. Zhang, Tetrahedron 1994, 50, 6077-6088; c) A. F. Burchat, J. M. Chong, S. B. Park, Tetrahedron Lett. 1993, 34, 51-54; d) W. H. Pearson, A. C. Lindbeck, J. W. Kampf, J. Am. Chem. Soc. 1993, 115, 2622-2636; e) T. R. Elworthy, A. I. Meyers, Tetrahedron 1994, 50, 6089-6096; f) M. E. Kopach, A. I. Meyers, J. Org. Chem. 1996, 61, 6764-6765; g) I. Coldham, R. Hufton, D. J. Snowden, J. Am. Chem. Soc. 1996, 118, 5322-5323; h) G. A. Weisenburger, P. Beak, ibid. 1996, 118, 12218-12219.
30. Examples of α-amino-substituted carbanion equivalents: a) S. T. Kerrick, P. Beak, J. Am. Chem. Soc. 1991, 113, 9708-9710; b) R. E. Gawley, Q. Zhang, Tetrahedron 1994, 50, 6077-6088; c) A. F. Burchat, J. M. Chong, S. B. Park, Tetrahedron Lett. 1993, 34, 51-54; d) W. H. Pearson, A. C. Lindbeck, J. W. Kampf, J. Am. Chem. Soc. 1993, 115, 2622-2636; e) T. R. Elworthy, A. I. Meyers, Tetrahedron 1994, 50, 6089-6096; f) M. E. Kopach, A. I. Meyers, J. Org. Chem. 1996, 61, 6764-6765; g) I. Coldham, R. Hufton, D. J. Snowden, J. Am. Chem. Soc. 1996, 118, 5322-5323; h) G. A. Weisenburger, P. Beak, ibid. 1996, 118, 12218-12219.
31. Examples of α-amino-substituted carbanion equivalents: a) S. T. Kerrick, P. Beak, J. Am. Chem. Soc. 1991, 113, 9708-9710; b) R. E. Gawley, Q. Zhang, Tetrahedron 1994, 50, 6077-6088; c) A. F. Burchat, J. M. Chong, S. B. Park, Tetrahedron Lett. 1993, 34, 51-54; d) W. H. Pearson, A. C. Lindbeck, J. W. Kampf, J. Am. Chem. Soc. 1993, 115, 2622-2636; e) T. R. Elworthy, A. I. Meyers, Tetrahedron 1994, 50, 6089-6096; f) M. E. Kopach, A. I. Meyers, J. Org. Chem. 1996, 61, 6764-6765; g) I. Coldham, R. Hufton, D. J. Snowden, J. Am. Chem. Soc. 1996, 118, 5322-5323; h) G. A. Weisenburger, P. Beak, ibid. 1996, 118, 12218-12219.
32. Examples of α-amino-substituted carbanion equivalents: a) S. T. Kerrick, P. Beak, J. Am. Chem. Soc. 1991, 113, 9708-9710; b) R. E. Gawley, Q. Zhang, Tetrahedron 1994, 50, 6077-6088; c) A. F. Burchat, J. M. Chong, S. B. Park, Tetrahedron Lett. 1993, 34, 51-54; d) W. H. Pearson, A. C. Lindbeck, J. W. Kampf, J. Am. Chem. Soc. 1993, 115, 2622-2636; e) T. R. Elworthy, A. I. Meyers, Tetrahedron 1994, 50, 6089-6096; f) M. E. Kopach, A. I. Meyers, J. Org. Chem. 1996, 61, 6764-6765; g) I. Coldham, R. Hufton, D. J. Snowden, J. Am. Chem. Soc. 1996, 118, 5322-5323; h) G. A. Weisenburger, P. Beak, ibid. 1996, 118, 12218-12219.
33. a) H.-J. Gais, G. Hellmann, H. Günther, F. Lopez, H. J. Lindner, S. Braun, Angew. Chem. 1989, 101, 1061-1063; Angew. Chem. Int. Ed. Engl. 1989, 28, 1025-1027;
34. a) H.-J. Gais, G. Hellmann, H. Günther, F. Lopez, H. J. Lindner, S. Braun, Angew. Chem. 1989, 101, 1061-1063; Angew. Chem. Int. Ed. Engl. 1989, 28, 1025-1027;
35. b) G. Raabe, H.-J. Gais, J. Fleischhauer, J. Am. Chem. Soc. 1996, 118, 4622-4630.
36. a) H. J. Reich, M. D. Bowe, J. Am. Chem. Soc. 1990, 112, 8994-8995;
37. b) H. J. Reich, R. R. Dykstra, Angew. Chem. 1993, 105, 1489-1491; Angew. Chem. Int. Ed. Engl. 1993, 32, 1469-1471;
38. b) H. J. Reich, R. R. Dykstra, Angew. Chem. 1993, 105, 1489-1491; Angew. Chem. Int. Ed. Engl. 1993, 32, 1469-1471;
39. c) J. Am. Chem. Soc. 1993, 115, 7041-7042;
40. d) H. J. Reich, K. J. Kulicke, ibid. 1995, 117, 6621-6622;
41. e) ibid. 1996, 118, 273-274;
42. f) R. W. Hoffmann, T. Rühl, J. Harbach, Liebigs Ann. Chem. 1992, 725-730;
43. g) R. W. Hoffmann, M. Julius, F. Chemla, T. Ruhland, G. Frenzen, Tetrahedron 1994, 50, 6049-6060;
44. h) H. Ahlbrecht, J. Harbach, R. W. Hoffmann, T. Ruhland, Liebigs Ann. 1995, 211-216;
45. i) R. W. Hoffmann, W. Klute, Chem. Eur. J. 1996, 2, 694-700;
46. k) R. K. Dress, T. Rölle, R. W. Hoffmann, Chem. Ber. 1995, 128, 673-677;
47. l) R. W. Hoffmann, R. K. Dress, T. Ruhland, A. Wenzel, ibid. 1995, 128, 861-870;
48. m) K. Brickmann, F. Hambloch, E. Spolaore, R. Brückner, ibid. 1994, 127, 1949-1957.
49. B. Kaiser, D. Hoppe, Angew. Chem. 1995, 107, 344-346; Angew. Chem. Int. Ed. Engl. 1995, 34, 323-325;
50. B. Kaiser, D. Hoppe, Angew. Chem. 1995, 107, 344-346; Angew. Chem. Int. Ed. Engl. 1995, 34, 323-325;
51. b) see also: T. Shinozuka, Y. Kikori, M. Asaoka, H. Takei, J. Chem. Soc. Perkin Trans. 1 1996, 119-120.
52. An α-(phenylselenoalkyl)magnesium compound that is configurationally stable at -78°C was prepared by kinetic resolution: W. Klute, M. Krüger, R. W. Hoffmann, Chem. Ber. 1996, 129, 633-638.
53. 1H NMR spectrum (300 MHz) by Δδ = 0.03.
54. 3 (0.8 mL) and comparison with corresponding spectra of the racemic compounds. Usually the highly enantiomerically enriched products showed only the signal for one enantiomer. In these cases the given enantiomeric excesses and detection limits were confirmed by addition of the racemic compounds.
55. Preparation of (R)-6 by enzyme-catalyzed hydrolysis of the racemic acetate with the lipase SAM II: K. Laumen. D. Breithoff, M. P. Schneider, J. Chem. Soc. Chem. Commun. 1988, 1459-1461.
56. Deprotonation of monothiocarbamates: a) S-alkyl: P. Beak, P. D. Becker, J. Org. Chem. 1982, 47, 3855-3861; b) S-1-alkenyl: D. Hoppe, L. Beckmann, R. Follmann, Angew. Chem. 1980, 92, 305-306; A ngew. Chem. Int. Ed. Engl. 1980, 19, 303-304.
57. Deprotonation of monothiocarbamates: a) S-alkyl: P. Beak, P. D. Becker, J. Org. Chem. 1982, 47, 3855-3861; b) S-1-alkenyl: D. Hoppe, L. Beckmann, R. Follmann, Angew. Chem. 1980, 92, 305-306; A ngew. Chem. Int. Ed. Engl. 1980, 19, 303-304.
58. Deprotonation of monothiocarbamates: a) S-alkyl: P. Beak, P. D. Becker, J. Org. Chem. 1982, 47, 3855-3861; b) S-1-alkenyl: D. Hoppe, L. Beckmann, R. Follmann, Angew. Chem. 1980, 92, 305-306; A ngew. Chem. Int. Ed. Engl. 1980, 19, 303-304.
59. -3. Flack parameter -0.01(3); hydrogen atoms were calculated and refined as riding. All data were collected on an Enraf Nonius CAD4 diffractometer. Programs used: data reduction MolEN, structure solution SHELXS-86, structure refinement SHEUCL-93. Crystallographic data (excluding structure factors) for the structures reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-100446. Copies of the data can be obtained free of charge on application to The Director, CCDC, 12 Union Road, Cambridge CB21EZ, UK (fax: int. code + (1223)336-033: e-mail: deposit@chemcrys.cam.ac.uk).
60. Reproduction of these results requires salt-free sec-butyllithium and highly pure, and in particular disulfide-free, 7; otherwise lower yields and enantiomeric excesses are registered.
61. An experiment in which (S)-8 is warmed to -2 to 0°C for 1 h and quenching with methyl chloroformate leads to ent-9b in 58% yield with 73% ee. A longer reaction time at 0°C causes severe decomposition.