Application of Enelike Reactions of Aldehydes with Vinyl Ethers: A Stereoconvergent Synthesis of (±)-Phyllanthocin

Journal of Organic Chemistry

Volumn 62, Issue 22, 1997, Pages 7806-7811

  Ciufolini, Marco A ^a   Zhu, Shuren ^a   Deaton, Melissa V ^a  

^a RICE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0001176163     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo971151w     Document Type: Article

References (35)

1. The term "ene reaction" is used herein solely to describe the outcome of our transformation, which is more likely to be mechanistically related to Prins-type reactions. Nomechanistic implications exist in such usage.
2. Deaton, M. V.; Ciufolini, M. A. Tetrahedron Lett. 1993, 34, 2409.
3. Cf. (a) Ciufolini, M. A. In Advances in Heterocyclic Natural Products Synthesis; Pearson, W. H., Ed.; JAI Press: Greenwich, CT, 1996; vol. 3, p 1.
4. Isolation: Kupchan, S. M.; LaVoie, E. J.; Branfman, A. R.; Fei, B. Y.; Bright, W. M.; Bryan, R. F. J. Am. Chem. Soc. 1977, 99, 3199.
5. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
6. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
7. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
8. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
9. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
10. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
11. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
12. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
13. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
14. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
15. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
16. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
17. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
18. Previous syntheses: (a) McGuirk, P. R.; Collum, D. B. J. Am. Chem. Soc. 1982, 104, 4496. (b) Williams, D. R.; Sit, S. Y. J. Am. Chem. Soc. 1984, 106, 2949. Burke, S. D.; Cobb, J. E. Tetrahedron Lett. 1986, 27, 4237. (d) Burke, S. D.; Cobb, J. E.; Takeuchi, K. J. Org. Chem. 1985, 50, 3420. (e) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1269. (f) Smith, A. B., III; Fukui, M.; Vaccaro, H. A.; Empfield, J. R. J. Am. Chem. Soc. 1991, 113, 2071. (g) Smith, A. B., III; Fukui, M. J. Am. Chem. Soc. 1987, 109, 1272. (h) Smith, A. B., III; Rivero, R. A.; Hale, K. J.; Vaccaro, H. A. J. Am. Chem. Soc. 1991, 113, 2092. (i) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J. J. Org. Chem. 1987, 52, 3706. (j) Martin, S. F.; Dappen, M. S.; Dupre, B.; Murphy, C. J.; Colapret, J. A. J. Org. Chem. 1989, 54, 2209. (k) Trost, B. M.; Edstrom, E. D. Angew. Chem., Int. Ed. Engl. 1990, 29, 520. Trost, B. M.; Kondo, Y. Tetrahedron Lett. 1991, 32, 1613. Synthetic Studies: (m) Linderman, R. J.; Viviani, F. G.; Kwochka, W. R. Tetrahedron Lett. 1992, 33, 3571. (n) Tenaglia, A.; Kammerer, F. Synlett 1996, 576.
19. 2S) and chromatography (80% EtOAc/hexanes, 68%).
20. This principle had been partly validated during earlier synthetic work on 1, particularly with respect to the stereochemistry of the spiroacetal, but not for entirestereochemical array of 2, as shown here.
21. For outstanding reviews see: (a) Snider, B. B. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: London, Springer-Verlag: Berlin, Germany, 1986. (b) Santelli, M; Pons, J. M. Lewis Acids and Selectivity in Organic Synthesis; CRC Press: Boca Raton, FL, 1996; Ch. 2. Fortunately, our enelike reaction tolerates a good range of spectator functionality. Recent example of carbonyl-ene reaction in terpene synthesis and bibliography: Snider, B. B.; Vo, N. H.; O'Neil S. V.; Foxman, B. M. J. Am. Chem. Soc. 1996, 118, 7644.
22. For outstanding reviews see: (a) Snider, B. B. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: London, Springer-Verlag: Berlin, Germany, 1986. (b) Santelli, M; Pons, J. M. Lewis Acids and Selectivity in Organic Synthesis; CRC Press: Boca Raton, FL, 1996; Ch. 2. Fortunately, our enelike reaction tolerates a good range of spectator functionality. Recent example of carbonyl-ene reaction in terpene synthesis and bibliography: Snider, B. B.; Vo, N. H.; O'Neil S. V.; Foxman, B. M. J. Am. Chem. Soc. 1996, 118, 7644.
23. For outstanding reviews see: (a) Snider, B. B. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: London, Springer-Verlag: Berlin, Germany, 1986. (b) Santelli, M; Pons, J. M. Lewis Acids and Selectivity in Organic Synthesis; CRC Press: Boca Raton, FL, 1996; Ch. 2. Fortunately, our enelike reaction tolerates a good range of spectator functionality. Recent example of carbonyl-ene reaction in terpene synthesis and bibliography: Snider, B. B.; Vo, N. H.; O'Neil S. V.; Foxman, B. M. J. Am. Chem. Soc. 1996, 118, 7644.
24. Theoretically, an intermediate of the type 13 could have been prepared starting with addition of the kinetic enolate of 3-methyl-4-[(tert-butyldimethylsilyl)oxy]-2-butanone to 9. However, reaction of this enolate with 9 proceeded poorly, while addition to simple aldehydes was uneventful. The reasons for this remain unclear.
25. Carlsen, P. H. J.; Katsuki, T.; Martin, V. S.; Sharpless, K. B. J. Org. Chem. 1981, 46, 3936.
26. 1H NMR spectra of 20 and 2, hardcopies of which are provided as Supporting Information.
27. Corey, E. J.; Chaykowsky, M. J. Am. Chem. Soc. 1965, 87, 1353.
28. 4 is normally selective for the equatorial alcohol in reduction of six-membered cyclic ketones, a well-documented steric effect is responsible for the opposite selectivity in the present system (ref. 5).
29. Corey, E. J.; Gross, A. W. Tetrahedron Lett. 1984, 25, 495.
30. An excellent survey of the unpredictable behavior of α-alkoxy ketones toward enolate formation may be found in: Gleave, D. M. Doctoral Dissertation, University of Saskatchewan, 1993.
31. Nitta, M.; Kobayashi, T. J. Chem. Soc., Chem. Commun. 1982, 877.
32. For an asymmetric variant of this chemistry see: Carreira, E.; Lee, W.; Singer,R. A. J. Am. Chem. Soc. 1995, 117, 3649.
33. 2CO. Elemental analyses were performed by Galbraith-Laboratories, Knoxville, TN.
34. 2CO. Elemental analyses were performed by Galbraith-Laboratories, Knoxville, TN.
35. 2CO. Elemental analyses were performed by Galbraith-Laboratories, Knoxville, TN.