Stereoselective Aldol-Type Cyclization Reaction Mediated by Dibutylboron Triflate/Diisopropylethylamine

Organic Letters

Volumn 6, Issue 1, 2004, Pages 123-126

  Das, Sanjib ^a   Li, Lian Sheng ^a   Sinha, Subhash C ^a  

^a SCRIPPS RESEARCH INSTITUTE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

BORON DERIVATIVE; DIBUTYLBORON TRIFLATE; ETHYLAMINE; ETHYLDIISOPROPYLAMINE; TRIFLUOROMETHANESULFONIC ACID; UNCLASSIFIED DRUG;

ALDOL REACTION; ARTICLE; CYCLIZATION; STEREOCHEMISTRY; SYNTHESIS;

EID: 0742286901     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol036229b     Document Type: Article

References (46)

1. For reviews on aldol reactions, see: (a) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595-1601 and references therein. (b) Palomo, C.; Oiarbide, M.; Garcîa, J. M. Chem. Eur. J. 2002, 8, 36-44. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Heathcock, C. H. In Asymmetric Synthesis; Morrison, J. D., Ed.; Academic Press: New York, 1984; Vol. 3, Chapter 2, part B, pp 111-212. (e) Evans, D. A.; Nelson, J. V.; Taber, T. R. Top. Stereochem. 1982, 13, 1-115.
2. For reviews on aldol reactions, see: (a) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595-1601 and references therein. (b) Palomo, C.; Oiarbide, M.; Garcîa, J. M. Chem. Eur. J. 2002, 8, 36-44. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Heathcock, C. H. In Asymmetric Synthesis; Morrison, J. D., Ed.; Academic Press: New York, 1984; Vol. 3, Chapter 2, part B, pp 111-212. (e) Evans, D. A.; Nelson, J. V.; Taber, T. R. Top. Stereochem. 1982, 13, 1-115.
3. For reviews on aldol reactions, see: (a) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595-1601 and references therein. (b) Palomo, C.; Oiarbide, M.; Garcîa, J. M. Chem. Eur. J. 2002, 8, 36-44. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Heathcock, C. H. In Asymmetric Synthesis; Morrison, J. D., Ed.; Academic Press: New York, 1984; Vol. 3, Chapter 2, part B, pp 111-212. (e) Evans, D. A.; Nelson, J. V.; Taber, T. R. Top. Stereochem. 1982, 13, 1-115.
4. For reviews on aldol reactions, see: (a) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595-1601 and references therein. (b) Palomo, C.; Oiarbide, M.; Garcîa, J. M. Chem. Eur. J. 2002, 8, 36-44. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Heathcock, C. H. In Asymmetric Synthesis; Morrison, J. D., Ed.; Academic Press: New York, 1984; Vol. 3, Chapter 2, part B, pp 111-212. (e) Evans, D. A.; Nelson, J. V.; Taber, T. R. Top. Stereochem. 1982, 13, 1-115.
5. For reviews on aldol reactions, see: (a) Alcaide, B.; Almendros, P. Eur. J. Org. Chem. 2002, 1595-1601 and references therein. (b) Palomo, C.; Oiarbide, M.; Garcîa, J. M. Chem. Eur. J. 2002, 8, 36-44. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Heathcock, C. H. In Asymmetric Synthesis; Morrison, J. D., Ed.; Academic Press: New York, 1984; Vol. 3, Chapter 2, part B, pp 111-212. (e) Evans, D. A.; Nelson, J. V.; Taber, T. R. Top. Stereochem. 1982, 13, 1-115.
6. (a) Mukaiyama, T.; Hayashi, M. Chem. Lett. 1974, 15-16.
7. For reviews, see: (b) Mukaiyama, T.; Murakami, M. Synthesis 1987, 1043-1054. (c) Mukaiyama, T. Org. React. 1982, 28, 238-248.
8. For reviews, see: (b) Mukaiyama, T.; Murakami, M. Synthesis 1987, 1043-1054. (c) Mukaiyama, T. Org. React. 1982, 28, 238-248.
9. For the intramolecular reactions, see: (a) Villanueva, O.; Prieto. J. A. J. Org. Chem. 1993, 58, 2718-2724. (b) Willson, T. M.; Kocienski, P.; Jarowicki, K.; Isaac, K.; Hitchcock, P. M.; Faller, A.; Campbell, S. F. Tetrahedron 1990, 46, 1767-1782. (c) Linderman, R. J.; Godfrey, A. J. Am. Chem. Soc. 1988, 110, 6249-6251. (d) Cockerill, G. S.; Kocienski, P. J. Chem. Soc., Perkin Trans. 1 1985, 2093-2100 and references therein. (e) For the condensation of silyl enol ethers with thio ketals, see: Trost, B. M.; Murayama, E. Tetrahedron Lett. 1982, 23, 1047-1050.
10. For the intramolecular reactions, see: (a) Villanueva, O.; Prieto. J. A. J. Org. Chem. 1993, 58, 2718-2724. (b) Willson, T. M.; Kocienski, P.; Jarowicki, K.; Isaac, K.; Hitchcock, P. M.; Faller, A.; Campbell, S. F. Tetrahedron 1990, 46, 1767-1782. (c) Linderman, R. J.; Godfrey, A. J. Am. Chem. Soc. 1988, 110, 6249-6251. (d) Cockerill, G. S.; Kocienski, P. J. Chem. Soc., Perkin Trans. 1 1985, 2093-2100 and references therein. (e) For the condensation of silyl enol ethers with thio ketals, see: Trost, B. M.; Murayama, E. Tetrahedron Lett. 1982, 23, 1047-1050.
11. For the intramolecular reactions, see: (a) Villanueva, O.; Prieto. J. A. J. Org. Chem. 1993, 58, 2718-2724. (b) Willson, T. M.; Kocienski, P.; Jarowicki, K.; Isaac, K.; Hitchcock, P. M.; Faller, A.; Campbell, S. F. Tetrahedron 1990, 46, 1767-1782. (c) Linderman, R. J.; Godfrey, A. J. Am. Chem. Soc. 1988, 110, 6249-6251. (d) Cockerill, G. S.; Kocienski, P. J. Chem. Soc., Perkin Trans. 1 1985, 2093-2100 and references therein. (e) For the condensation of silyl enol ethers with thio ketals, see: Trost, B. M.; Murayama, E. Tetrahedron Lett. 1982, 23, 1047-1050.
12. For the intramolecular reactions, see: (a) Villanueva, O.; Prieto. J. A. J. Org. Chem. 1993, 58, 2718-2724. (b) Willson, T. M.; Kocienski, P.; Jarowicki, K.; Isaac, K.; Hitchcock, P. M.; Faller, A.; Campbell, S. F. Tetrahedron 1990, 46, 1767-1782. (c) Linderman, R. J.; Godfrey, A. J. Am. Chem. Soc. 1988, 110, 6249-6251. (d) Cockerill, G. S.; Kocienski, P. J. Chem. Soc., Perkin Trans. 1 1985, 2093-2100 and references therein. (e) For the condensation of silyl enol ethers with thio ketals, see: Trost, B. M.; Murayama, E. Tetrahedron Lett. 1982, 23, 1047-1050.
13. For the intramolecular reactions, see: (a) Villanueva, O.; Prieto. J. A. J. Org. Chem. 1993, 58, 2718-2724. (b) Willson, T. M.; Kocienski, P.; Jarowicki, K.; Isaac, K.; Hitchcock, P. M.; Faller, A.; Campbell, S. F. Tetrahedron 1990, 46, 1767-1782. (c) Linderman, R. J.; Godfrey, A. J. Am. Chem. Soc. 1988, 110, 6249-6251. (d) Cockerill, G. S.; Kocienski, P. J. Chem. Soc., Perkin Trans. 1 1985, 2093-2100 and references therein. (e) For the condensation of silyl enol ethers with thio ketals, see: Trost, B. M.; Murayama, E. Tetrahedron Lett. 1982, 23, 1047-1050.
14. For intermolecular reactions, see: (a) Murata, S.; Suzuki, M.; Noyori, R. Tetrahedron 1988, 44, 4259-4275. (b) Noyori, R.; Murata, S.; Suzuki, M. Tetrahedron 1981, 37, 3899-3910. (c) Murata, S.; Suzuki, M.; Noyori, R. J. Am. Chem. Soc. 1980, 102, 3248-3249. For reactions catalyzed by a catalyst other than Ti(IV), see: (d) Ishitani, H.; Iwamoto, M. Tetrahedron Lett. 2003, 44, 299-301. (e) Le Roux, C.; Ciliberti, L.; Laurent-Robert, H.; Laporterie, A.; Dubac, J. Synlett 1998, 11, 1249-1251 and references therein.
15. For intermolecular reactions, see: (a) Murata, S.; Suzuki, M.; Noyori, R. Tetrahedron 1988, 44, 4259-4275. (b) Noyori, R.; Murata, S.; Suzuki, M. Tetrahedron 1981, 37, 3899-3910. (c) Murata, S.; Suzuki, M.; Noyori, R. J. Am. Chem. Soc. 1980, 102, 3248-3249. For reactions catalyzed by a catalyst other than Ti(IV), see: (d) Ishitani, H.; Iwamoto, M. Tetrahedron Lett. 2003, 44, 299-301. (e) Le Roux, C.; Ciliberti, L.; Laurent-Robert, H.; Laporterie, A.; Dubac, J. Synlett 1998, 11, 1249-1251 and references therein.
16. For intermolecular reactions, see: (a) Murata, S.; Suzuki, M.; Noyori, R. Tetrahedron 1988, 44, 4259-4275. (b) Noyori, R.; Murata, S.; Suzuki, M. Tetrahedron 1981, 37, 3899-3910. (c) Murata, S.; Suzuki, M.; Noyori, R. J. Am. Chem. Soc. 1980, 102, 3248-3249. For reactions catalyzed by a catalyst other than Ti(IV), see: (d) Ishitani, H.; Iwamoto, M. Tetrahedron Lett. 2003, 44, 299-301. (e) Le Roux, C.; Ciliberti, L.; Laurent-Robert, H.; Laporterie, A.; Dubac, J. Synlett 1998, 11, 1249-1251 and references therein.
17. For intermolecular reactions, see: (a) Murata, S.; Suzuki, M.; Noyori, R. Tetrahedron 1988, 44, 4259-4275. (b) Noyori, R.; Murata, S.; Suzuki, M. Tetrahedron 1981, 37, 3899-3910. (c) Murata, S.; Suzuki, M.; Noyori, R. J. Am. Chem. Soc. 1980, 102, 3248-3249. For reactions catalyzed by a catalyst other than Ti(IV), see: (d) Ishitani, H.; Iwamoto, M. Tetrahedron Lett. 2003, 44, 299-301. (e) Le Roux, C.; Ciliberti, L.; Laurent-Robert, H.; Laporterie, A.; Dubac, J. Synlett 1998, 11, 1249-1251 and references therein.
18. For intermolecular reactions, see: (a) Murata, S.; Suzuki, M.; Noyori, R. Tetrahedron 1988, 44, 4259-4275. (b) Noyori, R.; Murata, S.; Suzuki, M. Tetrahedron 1981, 37, 3899-3910. (c) Murata, S.; Suzuki, M.; Noyori, R. J. Am. Chem. Soc. 1980, 102, 3248-3249. For reactions catalyzed by a catalyst other than Ti(IV), see: (d) Ishitani, H.; Iwamoto, M. Tetrahedron Lett. 2003, 44, 299-301. (e) Le Roux, C.; Ciliberti, L.; Laurent-Robert, H.; Laporterie, A.; Dubac, J. Synlett 1998, 11, 1249-1251 and references therein.
19. For one-step intramolecular reactions to provide carbocyclic compounds, see: (a) Nicolaou, K. C.; Jennings, M. P.; Dagneau, P. Chem. Commun. 2002, 2480-2481. (b) Rubinger, M. M. M.; Mann, J. J. Chem. Res., Synop. 1999, 454-455. (c) Tokunaga, Y.; Yagihashi, M.; Ihara, M.; Fukumoto, K. J. Chem. Soc., Perkin Trans. 1 1997, 189-190. (d) Duhamel, P.; Deyine, A.; Dujardin, G.; Ple, G.; Poirier, J. M. J. Chem. Soc., Perkin Trans. 1 1995, 2104-2114. (e) Funk, R. L.; Fitzgerald, J. F.; Olmstead, T. A.; Para, K. S.; Wos, J. A. J. Am. Chem. Soc. 1993, 115, 8849-8850 and references therein.
20. For one-step intramolecular reactions to provide carbocyclic compounds, see: (a) Nicolaou, K. C.; Jennings, M. P.; Dagneau, P. Chem. Commun. 2002, 2480-2481. (b) Rubinger, M. M. M.; Mann, J. J. Chem. Res., Synop. 1999, 454-455. (c) Tokunaga, Y.; Yagihashi, M.; Ihara, M.; Fukumoto, K. J. Chem. Soc., Perkin Trans. 1 1997, 189-190. (d) Duhamel, P.; Deyine, A.; Dujardin, G.; Ple, G.; Poirier, J. M. J. Chem. Soc., Perkin Trans. 1 1995, 2104-2114. (e) Funk, R. L.; Fitzgerald, J. F.; Olmstead, T. A.; Para, K. S.; Wos, J. A. J. Am. Chem. Soc. 1993, 115, 8849-8850 and references therein.
21. For one-step intramolecular reactions to provide carbocyclic compounds, see: (a) Nicolaou, K. C.; Jennings, M. P.; Dagneau, P. Chem. Commun. 2002, 2480-2481. (b) Rubinger, M. M. M.; Mann, J. J. Chem. Res., Synop. 1999, 454-455. (c) Tokunaga, Y.; Yagihashi, M.; Ihara, M.; Fukumoto, K. J. Chem. Soc., Perkin Trans. 1 1997, 189-190. (d) Duhamel, P.; Deyine, A.; Dujardin, G.; Ple, G.; Poirier, J. M. J. Chem. Soc., Perkin Trans. 1 1995, 2104-2114. (e) Funk, R. L.; Fitzgerald, J. F.; Olmstead, T. A.; Para, K. S.; Wos, J. A. J. Am. Chem. Soc. 1993, 115, 8849-8850 and references therein.
22. For one-step intramolecular reactions to provide carbocyclic compounds, see: (a) Nicolaou, K. C.; Jennings, M. P.; Dagneau, P. Chem. Commun. 2002, 2480-2481. (b) Rubinger, M. M. M.; Mann, J. J. Chem. Res., Synop. 1999, 454-455. (c) Tokunaga, Y.; Yagihashi, M.; Ihara, M.; Fukumoto, K. J. Chem. Soc., Perkin Trans. 1 1997, 189-190. (d) Duhamel, P.; Deyine, A.; Dujardin, G.; Ple, G.; Poirier, J. M. J. Chem. Soc., Perkin Trans. 1 1995, 2104-2114. (e) Funk, R. L.; Fitzgerald, J. F.; Olmstead, T. A.; Para, K. S.; Wos, J. A. J. Am. Chem. Soc. 1993, 115, 8849-8850 and references therein.
23. For one-step intramolecular reactions to provide carbocyclic compounds, see: (a) Nicolaou, K. C.; Jennings, M. P.; Dagneau, P. Chem. Commun. 2002, 2480-2481. (b) Rubinger, M. M. M.; Mann, J. J. Chem. Res., Synop. 1999, 454-455. (c) Tokunaga, Y.; Yagihashi, M.; Ihara, M.; Fukumoto, K. J. Chem. Soc., Perkin Trans. 1 1997, 189-190. (d) Duhamel, P.; Deyine, A.; Dujardin, G.; Ple, G.; Poirier, J. M. J. Chem. Soc., Perkin Trans. 1 1995, 2104-2114. (e) Funk, R. L.; Fitzgerald, J. F.; Olmstead, T. A.; Para, K. S.; Wos, J. A. J. Am. Chem. Soc. 1993, 115, 8849-8850 and references therein.
24. For the one-step intermolecular reactions, see: (a) Cosp, A.; Romea, P.; Talavera, P.; Urpi, F.; Vilarrasa, J.; Font-Bardia, M.; Solans, X. Org. Lett. 2001, 3, 615-617. (b) Cosp, A.; Romea, P.; Urpi, F.; Vilarrasa, J. Tetrahedron Lett. 2001, 42, 4629-4631. (c) Keck, G. E.; Wager, C. A.; Wager, T. T.; Savin K. A.; Covel, J. A.; Mclaws, M. D.; Krishnamurthy, D.; Cee, V. J. Angew. Chem., Int. Ed. 2001, 40, 231-234. (d) Kobayashi, S.; Nishio K. J. Org. Chem. 1993, 58, 2647-2649. (e) Evans, D. A.; Urpi, F.; Somers, T. C.; Clark, J. S.; Bilodeau, M. T. J. Am. Chem. Soc. 1990, 112, 8215-8216. (f) Hashigaki, K.; Yoshioka, S.; Yamato. M. Synthesis 1986, 1004-1007.
25. For the one-step intermolecular reactions, see: (a) Cosp, A.; Romea, P.; Talavera, P.; Urpi, F.; Vilarrasa, J.; Font-Bardia, M.; Solans, X. Org. Lett. 2001, 3, 615-617. (b) Cosp, A.; Romea, P.; Urpi, F.; Vilarrasa, J. Tetrahedron Lett. 2001, 42, 4629-4631. (c) Keck, G. E.; Wager, C. A.; Wager, T. T.; Savin K. A.; Covel, J. A.; Mclaws, M. D.; Krishnamurthy, D.; Cee, V. J. Angew. Chem., Int. Ed. 2001, 40, 231-234. (d) Kobayashi, S.; Nishio K. J. Org. Chem. 1993, 58, 2647-2649. (e) Evans, D. A.; Urpi, F.; Somers, T. C.; Clark, J. S.; Bilodeau, M. T. J. Am. Chem. Soc. 1990, 112, 8215-8216. (f) Hashigaki, K.; Yoshioka, S.; Yamato. M. Synthesis 1986, 1004-1007.
26. For the one-step intermolecular reactions, see: (a) Cosp, A.; Romea, P.; Talavera, P.; Urpi, F.; Vilarrasa, J.; Font-Bardia, M.; Solans, X. Org. Lett. 2001, 3, 615-617. (b) Cosp, A.; Romea, P.; Urpi, F.; Vilarrasa, J. Tetrahedron Lett. 2001, 42, 4629-4631. (c) Keck, G. E.; Wager, C. A.; Wager, T. T.; Savin K. A.; Covel, J. A.; Mclaws, M. D.; Krishnamurthy, D.; Cee, V. J. Angew. Chem., Int. Ed. 2001, 40, 231-234. (d) Kobayashi, S.; Nishio K. J. Org. Chem. 1993, 58, 2647-2649. (e) Evans, D. A.; Urpi, F.; Somers, T. C.; Clark, J. S.; Bilodeau, M. T. J. Am. Chem. Soc. 1990, 112, 8215-8216. (f) Hashigaki, K.; Yoshioka, S.; Yamato. M. Synthesis 1986, 1004-1007.
27. For the one-step intermolecular reactions, see: (a) Cosp, A.; Romea, P.; Talavera, P.; Urpi, F.; Vilarrasa, J.; Font-Bardia, M.; Solans, X. Org. Lett. 2001, 3, 615-617. (b) Cosp, A.; Romea, P.; Urpi, F.; Vilarrasa, J. Tetrahedron Lett. 2001, 42, 4629-4631. (c) Keck, G. E.; Wager, C. A.; Wager, T. T.; Savin K. A.; Covel, J. A.; Mclaws, M. D.; Krishnamurthy, D.; Cee, V. J. Angew. Chem., Int. Ed. 2001, 40, 231-234. (d) Kobayashi, S.; Nishio K. J. Org. Chem. 1993, 58, 2647-2649. (e) Evans, D. A.; Urpi, F.; Somers, T. C.; Clark, J. S.; Bilodeau, M. T. J. Am. Chem. Soc. 1990, 112, 8215-8216. (f) Hashigaki, K.; Yoshioka, S.; Yamato. M. Synthesis 1986, 1004-1007.
28. For the one-step intermolecular reactions, see: (a) Cosp, A.; Romea, P.; Talavera, P.; Urpi, F.; Vilarrasa, J.; Font-Bardia, M.; Solans, X. Org. Lett. 2001, 3, 615-617. (b) Cosp, A.; Romea, P.; Urpi, F.; Vilarrasa, J. Tetrahedron Lett. 2001, 42, 4629-4631. (c) Keck, G. E.; Wager, C. A.; Wager, T. T.; Savin K. A.; Covel, J. A.; Mclaws, M. D.; Krishnamurthy, D.; Cee, V. J. Angew. Chem., Int. Ed. 2001, 40, 231-234. (d) Kobayashi, S.; Nishio K. J. Org. Chem. 1993, 58, 2647-2649. (e) Evans, D. A.; Urpi, F.; Somers, T. C.; Clark, J. S.; Bilodeau, M. T. J. Am. Chem. Soc. 1990, 112, 8215-8216. (f) Hashigaki, K.; Yoshioka, S.; Yamato. M. Synthesis 1986, 1004-1007.
29. For the one-step intermolecular reactions, see: (a) Cosp, A.; Romea, P.; Talavera, P.; Urpi, F.; Vilarrasa, J.; Font-Bardia, M.; Solans, X. Org. Lett. 2001, 3, 615-617. (b) Cosp, A.; Romea, P.; Urpi, F.; Vilarrasa, J. Tetrahedron Lett. 2001, 42, 4629-4631. (c) Keck, G. E.; Wager, C. A.; Wager, T. T.; Savin K. A.; Covel, J. A.; Mclaws, M. D.; Krishnamurthy, D.; Cee, V. J. Angew. Chem., Int. Ed. 2001, 40, 231-234. (d) Kobayashi, S.; Nishio K. J. Org. Chem. 1993, 58, 2647-2649. (e) Evans, D. A.; Urpi, F.; Somers, T. C.; Clark, J. S.; Bilodeau, M. T. J. Am. Chem. Soc. 1990, 112, 8215-8216. (f) Hashigaki, K.; Yoshioka, S.; Yamato. M. Synthesis 1986, 1004-1007.
30. 2NEt also mediates intermolecular aldol-type coupling of ketones with acetals and ketals; see: Li, L.-S.; Das, S. ; Sinha, S. C. Org. Lett. 2004, 6, 127-130.
31. (a) Evans, D. A.; Côté, B.; Coleman, P. J.; Connell, B. T. J. Am. Chem. Soc. 2003, 125, 10893-10898.
32. (b) Evans, D. A.; Coleman, P. J.; Côté, B. J. Org. Chem. 1997, 62, 788-789.
33. Arefolov, A.; Panek, J. S. Org. Lett. 2002, 4, 2397-2400.
34. Das, S.; Sinha, S. C. Unpublished results.
35. 2BOTf.
36. 2O, did not produce the desired products in our case.
37. 1H COSY, NOE, or NOESY spectra.
38. Inoue, T.; Mukaiyama, T. Bull. Chem. Soc. Jpn. 1980, 53, 174-178.
39. (a) Sammakia, T.; Smith, R. S. J. Am. Chem. Soc. 1994, 116, 7915-7916 and references therein.
40. (b) Denmark, S. E.; Willson, T. M.; Almstead, N. G. J. Am. Chem. Soc. 1989, 111, 9258-9260.
41. (c) Tanabe, Y.; Ohno, N. J. Org. Chem. 1988, 53, 1560-1563.
42. (d) Mohler, D. L.; Thompson, D. W. Tetrahedron Lett. 1987, 28, 2567-2570.
43. (e) Bartlett, P. A. J. Am. Chem. Soc. 1983, 105, 2088-2089.
44. For a review, see: (a) Chai, Y.; Hong, S.-P.; Lindsay, H. A.; McFarland, C. M.; McIntosh, M. C. Tetrahedron 2002, 58, 2905-2928. Also see: (b) Smith, A. B., III; Minbiole, K. P.; Verhoest, P. R.; Schelhaas, M. J. Am. Chem. Soc. 2001, 123, 10942-10953. (c) Petasis, N. A.; Lu, S.-P. Tetrahedron Lett. 1996, 37, 141-144.
45. For a review, see: (a) Chai, Y.; Hong, S.-P.; Lindsay, H. A.; McFarland, C. M.; McIntosh, M. C. Tetrahedron 2002, 58, 2905-2928. Also see: (b) Smith, A. B., III; Minbiole, K. P.; Verhoest, P. R.; Schelhaas, M. J. Am. Chem. Soc. 2001, 123, 10942-10953. (c) Petasis, N. A.; Lu, S.-P. Tetrahedron Lett. 1996, 37, 141-144.
46. For a review, see: (a) Chai, Y.; Hong, S.-P.; Lindsay, H. A.; McFarland, C. M.; McIntosh, M. C. Tetrahedron 2002, 58, 2905-2928. Also see: (b) Smith, A. B., III; Minbiole, K. P.; Verhoest, P. R.; Schelhaas, M. J. Am. Chem. Soc. 2001, 123, 10942-10953. (c) Petasis, N. A.; Lu, S.-P. Tetrahedron Lett. 1996, 37, 141-144.