Intramolecularly competitive Ireland Claisen rearrangements: Stereoselective synthesis of alkylidene cyclohexenes

Tetrahedron Letters

Volumn 39, Issue 39, 1998, Pages 7043-7046

  Zhang, Xiaowei ^a   McIntosh, Matthias C ^a  

^a UNIVERSITY OF ARKANSAS   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CYCLOHEXENE DERIVATIVE; KETENE DERIVATIVE;

ARTICLE; CHEMICAL ANALYSIS; CHEMICAL REACTION; STEREOCHEMISTRY; STEREOSPECIFICITY;

EID: 0032563874     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(98)01525-1     Document Type: Article

References (31)

1. (1) For reviews of the Claisen rearrangement, see: Wipf, P. in Comprehensive Organic Synthesis; Trost, B. M., Ed.; Pergamon: New York, 1991; Vol. 5, pp 827-873; Ziegler, F. E. Chem. Rev. 1988, 88, 1423; Pereira, S.; Srebnik, M. Aldrichimica Acta 1993, 26, 17 and references cited therein.
2. (1) For reviews of the Claisen rearrangement, see: Wipf, P. in Comprehensive Organic Synthesis; Trost, B. M., Ed.; Pergamon: New York, 1991; Vol. 5, pp 827-873; Ziegler, F. E. Chem. Rev. 1988, 88, 1423; Pereira, S.; Srebnik, M. Aldrichimica Acta 1993, 26, 17 and references cited therein.
3. (1) For reviews of the Claisen rearrangement, see: Wipf, P. in Comprehensive Organic Synthesis; Trost, B. M., Ed.; Pergamon: New York, 1991; Vol. 5, pp 827-873; Ziegler, F. E. Chem. Rev. 1988, 88, 1423; Pereira, S.; Srebnik, M. Aldrichimica Acta 1993, 26, 17 and references cited therein.
4. (2) Spino, C.; Liu, G.; Tu, N.; Girard, S. J. Org. Chem. 1994, 59, 5596.
5. (3) For intramolecularly competitive Claisen rearrangements of bis-allyl vinyl ethers in acyclic systems, see: Cresson, P.; Bancel, S. C. R. Acad. Sc., Ser. C. 1968, 266, 409; Parker, K. A.; Farmar, J. G. J. Org. Chem. 1986, 51, 4023; Nonoshita, K.; Banno, H.; Maruoka, K.; Yamamoto, H. J. Am. Chem. Soc. 1990, 112, 316.
6. (3) For intramolecularly competitive Claisen rearrangements of bis-allyl vinyl ethers in acyclic systems, see: Cresson, P.; Bancel, S. C. R. Acad. Sc., Ser. C. 1968, 266, 409; Parker, K. A.; Farmar, J. G. J. Org. Chem. 1986, 51, 4023; Nonoshita, K.; Banno, H.; Maruoka, K.; Yamamoto, H. J. Am. Chem. Soc. 1990, 112, 316.
7. (3) For intramolecularly competitive Claisen rearrangements of bis-allyl vinyl ethers in acyclic systems, see: Cresson, P.; Bancel, S. C. R. Acad. Sc., Ser. C. 1968, 266, 409; Parker, K. A.; Farmar, J. G. J. Org. Chem. 1986, 51, 4023; Nonoshita, K.; Banno, H.; Maruoka, K.; Yamamoto, H. J. Am. Chem. Soc. 1990, 112, 316.
8. (4) For intramolecularly competitive Claisen rearrangements of bis-allyl vinyl ethers derived from 1-cycloalkene carboxaldehydes, see: Bancel, S.; Cresson, P. C. R. Acad. Sc., Ser. C. 1969, 268, 1535; Hudlicky, T.; Kwart, L. D.; Tiedje, M. H.; Ranu, B. C.; Short, R. P.; Frazier, J. O.; Rigby, H. L. Synthesis 1986, 716; Tanis, S.; McMills, M. C.; Scahill, T. A.; Kloosterman, D. A. Tetrahedron Lett. 1990, 31, 1977.
9. (4) For intramolecularly competitive Claisen rearrangements of bis-allyl vinyl ethers derived from 1-cycloalkene carboxaldehydes, see: Bancel, S.; Cresson, P. C. R. Acad. Sc., Ser. C. 1969, 268, 1535; Hudlicky, T.; Kwart, L. D.; Tiedje, M. H.; Ranu, B. C.; Short, R. P.; Frazier, J. O.; Rigby, H. L. Synthesis 1986, 716; Tanis, S.; McMills, M. C.; Scahill, T. A.; Kloosterman, D. A. Tetrahedron Lett. 1990, 31, 1977.
10. (4) For intramolecularly competitive Claisen rearrangements of bis-allyl vinyl ethers derived from 1-cycloalkene carboxaldehydes, see: Bancel, S.; Cresson, P. C. R. Acad. Sc., Ser. C. 1969, 268, 1535; Hudlicky, T.; Kwart, L. D.; Tiedje, M. H.; Ranu, B. C.; Short, R. P.; Frazier, J. O.; Rigby, H. L. Synthesis 1986, 716; Tanis, S.; McMills, M. C.; Scahill, T. A.; Kloosterman, D. A. Tetrahedron Lett. 1990, 31, 1977.
11. (5) (a) Cresson, P. Bull. Soc. Chim. Fr. 1964, 2618; ibid, 2629; Marbet, R.; Saucy, G. Helv. Chim. Acta 1967, 50, 218;
12. (5) (a) Cresson, P. Bull. Soc. Chim. Fr. 1964, 2618; ibid, 2629; Marbet, R.; Saucy, G. Helv. Chim. Acta 1967, 50, 218;
13. (5) (a) Cresson, P. Bull. Soc. Chim. Fr. 1964, 2618; ibid, 2629; Marbet, R.; Saucy, G. Helv. Chim. Acta 1967, 50, 218;
14. (b) Chillous, S. E.; Hart, D. J.; Hutchinson, D. K. J. Org. Chem. 1982, 47, 5420.
15. (6) For intramolecularly competitive anionic oxy-Cope rearrangements, see: Paquette, L. A.; Guevel, R.; Sauer, D. R. Tetrahedron Lett. 1992, 33, 923; Still, W. C.; Murata, S.; Revial, G.; Yoshihara, K. J. Am. Chem. Soc. 1983, 105, 625 and references cited therein.
16. (6) For intramolecularly competitive anionic oxy-Cope rearrangements, see: Paquette, L. A.; Guevel, R.; Sauer, D. R. Tetrahedron Lett. 1992, 33, 923; Still, W. C.; Murata, S.; Revial, G.; Yoshihara, K. J. Am. Chem. Soc. 1983, 105, 625 and references cited therein.
17. 13C-NMR, HRMS and IR. Alkene geometries were determined by NOE experiments and/or X-ray crystallography (ref 10).
18. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
19. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
20. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
21. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
22. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
23. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
24. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
25. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
26. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
27. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
28. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
29. (8) For some alternative approaches to stereoselective preparation of alkylidene cycloalkenes, see: Larock, R. C.; He, Y.; Leong, W. W.; Han, X.; Refvik, M. D.; Zenner, J. M. J. Org. Chem. 1998, 63, 2154; Chamakh, A.; Amri, H. Tetrahedron Lett. 1998, 39, 375; Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1998, 39, 4417; Murakami, M., Itami, K.; Ito, Y. J. Am. Chem. Soc. 1997, 119, 716; Terakado, M.; Miyazawa, M.; Yamamoto, K. Synlett 1994, 134; Nuss, J. M.; Rennels, R. A., Levine, B.H. J. Am. Chem. Soc. 1993, 115, 6991; Brown, S.; Clarkson, S.; Grigg, R.; Sridharan, V. Tetrahedron Lett. 1993, 34, 157; Trost, B. M.; Dumas, J. Tetrahedron Lett. 1993, 34, 19; Owczarczyk, Z.; Lamaty, F.; Vawter, E. J.; Negishi, E.-i. J. Am. Chem. Soc. 1992, 114, 10091; Reich, H. J.; Eisenhart, E. K.; Whipple, W. L.; Kelly, M. J. J. Am. Chem. Soc. 1988, 110, 6432; Okamura, W. H.; Peter, R.; Reischl, W. J. Am. Chem. Soc. 1985, 107, 1034; Paquette, L. A.; Yan, T.-H.; Wells, G. J. J. Org. Chem. 1984, 49, 3610. See also ref 2.
30. 2 248.1776; found 248.1784.
31. (10) The structure of diene 14b was determined unambiguously by X-ray crystallography of the corresponding (S)-α-methylbenzamide.