The Exocyclic Effect: Protecting Group Strategy to Enhance Stereoselectivity in Hydrogen Transfer Reactions of Acyclic Free Radicals

Journal of Organic Chemistry

Volumn 62, Issue 26, 1997, Pages 9276-9283

  Guindon, Yvan ^a,b   Faucher, Anne Marie ^c   Bourque, Élyse ^c   Caron, Valérie ^a,c   Jung, Grace ^a,b   Landry, Serge R ^a,c  

^a CLIN RESEARCH INSTITUTE OF MONTREAL   (Canada)

^b UNIVERSITÉ DE MONTRÉAL   (Canada)

^c BOEHRINGER INGELHEIM CANADA LTD   (Canada)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000014261     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo971595s     Document Type: Article

References (59)

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13. Selected examples involving the use of chiral auxiliaries: (a) Crich, D.; Davies, J. W. Tetrahedron Lett. 1987, 28, 4205. (b) Porter, N. A.; Scott, D. M.; Lacher, B.; Giese, B.; Zeitz, H. G.; Lindner, H. J. J. Am. Chem. Soc. 1989, 111, 8311. (c) Curran, D. P.; Qi, H.; Geib, S. J.; DeMello, N. C. J. Am. Chem. Soc. 1994, 116, 3131. (d) Porter, N. A.; Carter, R. L.; Mero, C. L.; Roepel, M. G.; Curran, D. P. Tetrahedron 1996, 52, 4181, and references therein.
14. Selected examples involving the use of chiral auxiliaries: (a) Crich, D.; Davies, J. W. Tetrahedron Lett. 1987, 28, 4205. (b) Porter, N. A.; Scott, D. M.; Lacher, B.; Giese, B.; Zeitz, H. G.; Lindner, H. J. J. Am. Chem. Soc. 1989, 111, 8311. (c) Curran, D. P.; Qi, H.; Geib, S. J.; DeMello, N. C. J. Am. Chem. Soc. 1994, 116, 3131. (d) Porter, N. A.; Carter, R. L.; Mero, C. L.; Roepel, M. G.; Curran, D. P. Tetrahedron 1996, 52, 4181, and references therein.
15. Selected examples involving the use of chiral auxiliaries: (a) Crich, D.; Davies, J. W. Tetrahedron Lett. 1987, 28, 4205. (b) Porter, N. A.; Scott, D. M.; Lacher, B.; Giese, B.; Zeitz, H. G.; Lindner, H. J. J. Am. Chem. Soc. 1989, 111, 8311. (c) Curran, D. P.; Qi, H.; Geib, S. J.; DeMello, N. C. J. Am. Chem. Soc. 1994, 116, 3131. (d) Porter, N. A.; Carter, R. L.; Mero, C. L.; Roepel, M. G.; Curran, D. P. Tetrahedron 1996, 52, 4181, and references therein.
16. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
17. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
18. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
19. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
20. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
21. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
22. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
23. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
24. For the use of monodentate Lewis acids, see: (a) Renaud, P.; Moufid, N.; Kuo, L. H.; Curran, D. P. J. Org. Chem. 1994, 59, 3547. (b) Renaud, P.; Ribezzo, M. J. Am. Chem. Soc. 1991, 113, 7803. (c) Curran, D. P.; Kuo, L. H. J. Org. Chem. 1994, 59, 3259. (d) Nishida, M.; Ueyama, E.; Hayashi, H.; Ohtake, Y.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O.; Nishida, A.; Kawahara, N. J. Am. Chem. Soc. 1994, 116, 6455. (e) Renaud, P.; Bourquard, T.; Gerster, M.; Moufid, N. Angew. Chem., Int. Ed. Engl. 1994, 33, 1601. (f) Nishida, M.; Hayashi, H.; Yamaura, Y.; Yanaginuma, E.; Yonemitsu, O. Tetrahedron Lett. 1995, 36, 269. (g) Murakata, M.; Tsutsui, H.; Hoshino, O. J. Chem. Soc., Chem. Commun. 1995, 481. (h) Urabe, H.; Kobayashi, K.; Sato, F. J. Chem. Soc., Chem. Commun. 1995, 1043. (i) Moufid, N.; Renaud, P.; Hassler, C.; Giese, B. Helv. Chim. Acta 1995, 78, 1006.
25. For the use of bidentate Lewis acids, see: (a) Guindon, Y.; Lavallée, J.-F.; Llinas-Brunet, M.; Horner, G.; Rancourt, J. J. Am. Chem. Soc. 1991, 113, 9701. (b) Guindon, Y.; Guérin, B.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Synlett. 1995, 449. (c) Guindon, Y.; Guérin, B.; Rancourt, J.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Pure Appl. Chem. 1996, 68, 89. (d) Toru, T.; Watanabe, Y.; Tsusaka, M.; Ueno, Y. J. Am. Chem. Soc. 1993, 115, 10464. (e) Rück, K.; Kunz, H. Synthesis 1993, 1018. (f) Nagano, H.; Kuno, Y. J. Chem. Soc., Chem. Commun. 1994, 987. (g) Yamamoto, Y.; Onuki, S; Yumoto, M.; Asao, N. J. Am. Chem. Soc. 1994, 116, 421. (h) Gerster, M.; Audergon, L.; Moufid, N.; Renaud, P. Tetrahedron Lett. 1996, 37, 6335.
26. For the use of bidentate Lewis acids, see: (a) Guindon, Y.; Lavallée, J.-F.; Llinas-Brunet, M.; Horner, G.; Rancourt, J. J. Am. Chem. Soc. 1991, 113, 9701. (b) Guindon, Y.; Guérin, B.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Synlett. 1995, 449. (c) Guindon, Y.; Guérin, B.; Rancourt, J.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Pure Appl. Chem. 1996, 68, 89. (d) Toru, T.; Watanabe, Y.; Tsusaka, M.; Ueno, Y. J. Am. Chem. Soc. 1993, 115, 10464. (e) Rück, K.; Kunz, H. Synthesis 1993, 1018. (f) Nagano, H.; Kuno, Y. J. Chem. Soc., Chem. Commun. 1994, 987. (g) Yamamoto, Y.; Onuki, S; Yumoto, M.; Asao, N. J. Am. Chem. Soc. 1994, 116, 421. (h) Gerster, M.; Audergon, L.; Moufid, N.; Renaud, P. Tetrahedron Lett. 1996, 37, 6335.
27. For the use of bidentate Lewis acids, see: (a) Guindon, Y.; Lavallée, J.-F.; Llinas-Brunet, M.; Horner, G.; Rancourt, J. J. Am. Chem. Soc. 1991, 113, 9701. (b) Guindon, Y.; Guérin, B.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Synlett. 1995, 449. (c) Guindon, Y.; Guérin, B.; Rancourt, J.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Pure Appl. Chem. 1996, 68, 89. (d) Toru, T.; Watanabe, Y.; Tsusaka, M.; Ueno, Y. J. Am. Chem. Soc. 1993, 115, 10464. (e) Rück, K.; Kunz, H. Synthesis 1993, 1018. (f) Nagano, H.; Kuno, Y. J. Chem. Soc., Chem. Commun. 1994, 987. (g) Yamamoto, Y.; Onuki, S; Yumoto, M.; Asao, N. J. Am. Chem. Soc. 1994, 116, 421. (h) Gerster, M.; Audergon, L.; Moufid, N.; Renaud, P. Tetrahedron Lett. 1996, 37, 6335.
28. For the use of bidentate Lewis acids, see: (a) Guindon, Y.; Lavallée, J.-F.; Llinas-Brunet, M.; Horner, G.; Rancourt, J. J. Am. Chem. Soc. 1991, 113, 9701. (b) Guindon, Y.; Guérin, B.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Synlett. 1995, 449. (c) Guindon, Y.; Guérin, B.; Rancourt, J.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Pure Appl. Chem. 1996, 68, 89. (d) Toru, T.; Watanabe, Y.; Tsusaka, M.; Ueno, Y. J. Am. Chem. Soc. 1993, 115, 10464. (e) Rück, K.; Kunz, H. Synthesis 1993, 1018. (f) Nagano, H.; Kuno, Y. J. Chem. Soc., Chem. Commun. 1994, 987. (g) Yamamoto, Y.; Onuki, S; Yumoto, M.; Asao, N. J. Am. Chem. Soc. 1994, 116, 421. (h) Gerster, M.; Audergon, L.; Moufid, N.; Renaud, P. Tetrahedron Lett. 1996, 37, 6335.
29. For the use of bidentate Lewis acids, see: (a) Guindon, Y.; Lavallée, J.-F.; Llinas-Brunet, M.; Horner, G.; Rancourt, J. J. Am. Chem. Soc. 1991, 113, 9701. (b) Guindon, Y.; Guérin, B.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Synlett. 1995, 449. (c) Guindon, Y.; Guérin, B.; Rancourt, J.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Pure Appl. Chem. 1996, 68, 89. (d) Toru, T.; Watanabe, Y.; Tsusaka, M.; Ueno, Y. J. Am. Chem. Soc. 1993, 115, 10464. (e) Rück, K.; Kunz, H. Synthesis 1993, 1018. (f) Nagano, H.; Kuno, Y. J. Chem. Soc., Chem. Commun. 1994, 987. (g) Yamamoto, Y.; Onuki, S; Yumoto, M.; Asao, N. J. Am. Chem. Soc. 1994, 116, 421. (h) Gerster, M.; Audergon, L.; Moufid, N.; Renaud, P. Tetrahedron Lett. 1996, 37, 6335.
30. For the use of bidentate Lewis acids, see: (a) Guindon, Y.; Lavallée, J.-F.; Llinas-Brunet, M.; Horner, G.; Rancourt, J. J. Am. Chem. Soc. 1991, 113, 9701. (b) Guindon, Y.; Guérin, B.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Synlett. 1995, 449. (c) Guindon, Y.; Guérin, B.; Rancourt, J.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Pure Appl. Chem. 1996, 68, 89. (d) Toru, T.; Watanabe, Y.; Tsusaka, M.; Ueno, Y. J. Am. Chem. Soc. 1993, 115, 10464. (e) Rück, K.; Kunz, H. Synthesis 1993, 1018. (f) Nagano, H.; Kuno, Y. J. Chem. Soc., Chem. Commun. 1994, 987. (g) Yamamoto, Y.; Onuki, S; Yumoto, M.; Asao, N. J. Am. Chem. Soc. 1994, 116, 421. (h) Gerster, M.; Audergon, L.; Moufid, N.; Renaud, P. Tetrahedron Lett. 1996, 37, 6335.
31. For the use of bidentate Lewis acids, see: (a) Guindon, Y.; Lavallée, J.-F.; Llinas-Brunet, M.; Horner, G.; Rancourt, J. J. Am. Chem. Soc. 1991, 113, 9701. (b) Guindon, Y.; Guérin, B.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Synlett. 1995, 449. (c) Guindon, Y.; Guérin, B.; Rancourt, J.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Pure Appl. Chem. 1996, 68, 89. (d) Toru, T.; Watanabe, Y.; Tsusaka, M.; Ueno, Y. J. Am. Chem. Soc. 1993, 115, 10464. (e) Rück, K.; Kunz, H. Synthesis 1993, 1018. (f) Nagano, H.; Kuno, Y. J. Chem. Soc., Chem. Commun. 1994, 987. (g) Yamamoto, Y.; Onuki, S; Yumoto, M.; Asao, N. J. Am. Chem. Soc. 1994, 116, 421. (h) Gerster, M.; Audergon, L.; Moufid, N.; Renaud, P. Tetrahedron Lett. 1996, 37, 6335.
32. For the use of bidentate Lewis acids, see: (a) Guindon, Y.; Lavallée, J.-F.; Llinas-Brunet, M.; Horner, G.; Rancourt, J. J. Am. Chem. Soc. 1991, 113, 9701. (b) Guindon, Y.; Guérin, B.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Synlett. 1995, 449. (c) Guindon, Y.; Guérin, B.; Rancourt, J.; Chabot, C.; Mackintosh, N.; Ogilvie, W. W. Pure Appl. Chem. 1996, 68, 89. (d) Toru, T.; Watanabe, Y.; Tsusaka, M.; Ueno, Y. J. Am. Chem. Soc. 1993, 115, 10464. (e) Rück, K.; Kunz, H. Synthesis 1993, 1018. (f) Nagano, H.; Kuno, Y. J. Chem. Soc., Chem. Commun. 1994, 987. (g) Yamamoto, Y.; Onuki, S; Yumoto, M.; Asao, N. J. Am. Chem. Soc. 1994, 116, 421. (h) Gerster, M.; Audergon, L.; Moufid, N.; Renaud, P. Tetrahedron Lett. 1996, 37, 6335.
33. For the use of chiral Lewis acids, see: (a) Sibi, M. P.; Jasperse, C. P.; Ji, J. G. J. Am. Chem. Soc. 1995, 117, 10779. (b) Wu, J. H.; Radinov, R.; Porter, N. A. J. Am. Chem. Soc. 1995, 117, 11029. (c) Sibi, M. P.; Ji, J. G. J. Am. Chem. Soc. 1996, 118, 3063. (d) Sibi, M. P.; Ji, J. G. Angew. Chem., Int. Ed. Engl. 1996, 35, 190. (e) Sibi, M. P.; Ji, J. G.; Wu, J. H.; Gurtler, S.; Porter, N. A. J. Am. Chem. Soc. 1996, 118, 9200. (f) Fhal, A. R.; Renaud, P. Tetrahedron Lett. 1997, 38, 2661.
34. For the use of chiral Lewis acids, see: (a) Sibi, M. P.; Jasperse, C. P.; Ji, J. G. J. Am. Chem. Soc. 1995, 117, 10779. (b) Wu, J. H.; Radinov, R.; Porter, N. A. J. Am. Chem. Soc. 1995, 117, 11029. (c) Sibi, M. P.; Ji, J. G. J. Am. Chem. Soc. 1996, 118, 3063. (d) Sibi, M. P.; Ji, J. G. Angew. Chem., Int. Ed. Engl. 1996, 35, 190. (e) Sibi, M. P.; Ji, J. G.; Wu, J. H.; Gurtler, S.; Porter, N. A. J. Am. Chem. Soc. 1996, 118, 9200. (f) Fhal, A. R.; Renaud, P. Tetrahedron Lett. 1997, 38, 2661.
35. For the use of chiral Lewis acids, see: (a) Sibi, M. P.; Jasperse, C. P.; Ji, J. G. J. Am. Chem. Soc. 1995, 117, 10779. (b) Wu, J. H.; Radinov, R.; Porter, N. A. J. Am. Chem. Soc. 1995, 117, 11029. (c) Sibi, M. P.; Ji, J. G. J. Am. Chem. Soc. 1996, 118, 3063. (d) Sibi, M. P.; Ji, J. G. Angew. Chem., Int. Ed. Engl. 1996, 35, 190. (e) Sibi, M. P.; Ji, J. G.; Wu, J. H.; Gurtler, S.; Porter, N. A. J. Am. Chem. Soc. 1996, 118, 9200. (f) Fhal, A. R.; Renaud, P. Tetrahedron Lett. 1997, 38, 2661.
36. For the use of chiral Lewis acids, see: (a) Sibi, M. P.; Jasperse, C. P.; Ji, J. G. J. Am. Chem. Soc. 1995, 117, 10779. (b) Wu, J. H.; Radinov, R.; Porter, N. A. J. Am. Chem. Soc. 1995, 117, 11029. (c) Sibi, M. P.; Ji, J. G. J. Am. Chem. Soc. 1996, 118, 3063. (d) Sibi, M. P.; Ji, J. G. Angew. Chem., Int. Ed. Engl. 1996, 35, 190. (e) Sibi, M. P.; Ji, J. G.; Wu, J. H.; Gurtler, S.; Porter, N. A. J. Am. Chem. Soc. 1996, 118, 9200. (f) Fhal, A. R.; Renaud, P. Tetrahedron Lett. 1997, 38, 2661.
37. For the use of chiral Lewis acids, see: (a) Sibi, M. P.; Jasperse, C. P.; Ji, J. G. J. Am. Chem. Soc. 1995, 117, 10779. (b) Wu, J. H.; Radinov, R.; Porter, N. A. J. Am. Chem. Soc. 1995, 117, 11029. (c) Sibi, M. P.; Ji, J. G. J. Am. Chem. Soc. 1996, 118, 3063. (d) Sibi, M. P.; Ji, J. G. Angew. Chem., Int. Ed. Engl. 1996, 35, 190. (e) Sibi, M. P.; Ji, J. G.; Wu, J. H.; Gurtler, S.; Porter, N. A. J. Am. Chem. Soc. 1996, 118, 9200. (f) Fhal, A. R.; Renaud, P. Tetrahedron Lett. 1997, 38, 2661.
38. For the use of chiral Lewis acids, see: (a) Sibi, M. P.; Jasperse, C. P.; Ji, J. G. J. Am. Chem. Soc. 1995, 117, 10779. (b) Wu, J. H.; Radinov, R.; Porter, N. A. J. Am. Chem. Soc. 1995, 117, 11029. (c) Sibi, M. P.; Ji, J. G. J. Am. Chem. Soc. 1996, 118, 3063. (d) Sibi, M. P.; Ji, J. G. Angew. Chem., Int. Ed. Engl. 1996, 35, 190. (e) Sibi, M. P.; Ji, J. G.; Wu, J. H.; Gurtler, S.; Porter, N. A. J. Am. Chem. Soc. 1996, 118, 9200. (f) Fhal, A. R.; Renaud, P. Tetrahedron Lett. 1997, 38, 2661.
39. For intramolecular hydrogen bonding, see: (a) Kündig, E. P.; Xu, L.-H.; Romanens, P. Tetrahedron Lett. 1995, 36, 4047. (b) Curran, D. P.; Abraham, A. C.; Liu, H.-T. J. Org. Chem. 1991, 56, 4335. (c) Hanessian, S.; Yang, H.; Schaum, R. J. Am. Chem. Soc. 1996, 118, 2507.
40. For intramolecular hydrogen bonding, see: (a) Kündig, E. P.; Xu, L.-H.; Romanens, P. Tetrahedron Lett. 1995, 36, 4047. (b) Curran, D. P.; Abraham, A. C.; Liu, H.-T. J. Org. Chem. 1991, 56, 4335. (c) Hanessian, S.; Yang, H.; Schaum, R. J. Am. Chem. Soc. 1996, 118, 2507.
41. For intramolecular hydrogen bonding, see: (a) Kündig, E. P.; Xu, L.-H.; Romanens, P. Tetrahedron Lett. 1995, 36, 4047. (b) Curran, D. P.; Abraham, A. C.; Liu, H.-T. J. Org. Chem. 1991, 56, 4335. (c) Hanessian, S.; Yang, H.; Schaum, R. J. Am. Chem. Soc. 1996, 118, 2507.
42. Guindon, Y.; Yoakim, C.; Lemieux, R.; Boisvert, L.; Delorme, D.; Lavallée, J.-F.; Tetrahedron Lett. 1990, 31, 2845.
43. Guindon, Y.; Lavallée, J.-F.; Boisvert, L.; Chabot, C.; Delorme, D.; Yoakim, C.; Hall, D.; Lemieux, R.; Simoneau, B. Tetrahedron Lett. 1991, 32, 27.
44. Guindon, Y.; Yoakim, C.; Gorys, V.; Ogilvie, W. W.; Delorme, D.; Renaud, J.; Robinson, G.; Lavallée, J.-F.; Slassi, A.; Jung, G.; Rancourt, J.; Durkin, K.; Liotta, D. J. Org. Chem. 1994, 59, 1166.
45. Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis, 2nd ed.; John Wiley & Sons, Inc.: New York, 1991; pp 118-142.
46. Guindon, Y.; Slassi, A.; Rancourt, J.; Bantle, G.; Bencheqroun, M.; Murtagh, L.; Ghiro, É.; Jung, G. J. Org. Chem. 1995, 60, 288.
47. Gouzoules, F. H.; Whitney, R. A. J. Org. Chem. 1986, 51, 2024-2030.
48. 1 substituent in the radical shown in eq 1. In contrast to such exocyclic radicals, which undergo hydrogen transfer to give predominantly anti-products, endocyclic radicals derived from bidentate Lewis acid chelation between the ester carbonyl and β-heteroatom react with syn-selection.
49. This model was first proposed by Hart: (a) Hart, D. J.; Huang, H.-C. Tetrahedron Lett. 1985, 26, 3749. (b) Hart, D. J.; Krishnamurthy, R. J. Org. Chem. 1992, 57, 4457. Ab initio calculations have been used to reveal the collinear arrangement of attacking and leaving radicals in the transition state of a hydrogen transfer reaction: Dakternieks, D., Henry, D. J.; Schiesser, C. H. J. Chem. Soc., Perkin Trans. 2, 1997, 1665.
50. This model was first proposed by Hart: (a) Hart, D. J.; Huang, H.-C. Tetrahedron Lett. 1985, 26, 3749. (b) Hart, D. J.; Krishnamurthy, R. J. Org. Chem. 1992, 57, 4457. Ab initio calculations have been used to reveal the collinear arrangement of attacking and leaving radicals in the transition state of a hydrogen transfer reaction: Dakternieks, D., Henry, D. J.; Schiesser, C. H. J. Chem. Soc., Perkin Trans. 2, 1997, 1665.
51. This model was first proposed by Hart: (a) Hart, D. J.; Huang, H.-C. Tetrahedron Lett. 1985, 26, 3749. (b) Hart, D. J.; Krishnamurthy, R. J. Org. Chem. 1992, 57, 4457. Ab initio calculations have been used to reveal the collinear arrangement of attacking and leaving radicals in the transition state of a hydrogen transfer reaction: Dakternieks, D., Henry, D. J.; Schiesser, C. H. J. Chem. Soc., Perkin Trans. 2, 1997, 1665.
52. Durkin, K.; Liotta, D.; Rancourt, J.; Lavallée, J.-F.; Boisvert, L.; Guindon, Y. J. Am. Chem. Soc. 1992, 114, 4912.
53. Giese, B.; Damm, W.; Wetterich, F.; Zeitz, H.-G. Tetrahedron Lett. 1992, 33, 1863.
54. The ground state conformer of the radical is supported by calculations and ESR studies: Giese, B.; Damm, W.; Wetterich, F.; Zeitz, H.-G.; Rancourt, J.; Guindon, Y. Tetrahedron Lett. 1993, 34, 5885.
55. Paddon-Row, M. N.; Rondan, N. G.; Houk, K. N. J. Am. Chem. Soc. 1982, 104, 7162.
56. Brion, F. Tetrahedron Lett. 1982, 23, 5299.
57. The similarity in anti:syn ratios when tributyl deuteride was used showed that the role of intramolecular hydrogen transfer was negligible.
58. The minor (syn) radical reduction product was synthesized via a different sequence for characterization purposes: Aldol condensation of the appropriate aldehyde with tert-butyl propionate instead of tert-butyl 2-(phenylselenenyl)propionate, followed by in situ deprotection of the tert-butyldimethylsilyl ether and formation of the acetal. This sequence afforded the same products as the radical reduction but where the syn diastereomer is favored.
59. 2O (5 equiv). This modification gave an anti:syn ratio of 1.4:1 and 3.5:1 for 34 and 31, respectively.