Enantiospecific synthesis of (-)-slaframine and related hydroxylated indolizidines. Utilization of a nucleophilic alaninol synthon derived from serine

Journal of Organic Chemistry

Volumn 64, Issue 17, 1999, Pages 6434-6442

  Sibi, Mukund P ^a   Christensen, James W ^a  

^a NORTH DAKOTA STATE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

1 HYDROXYINDOLIZIDINE; 2 HYDROXY 6 AMINOINDOLIZIDINE; ALKALOID; CASTANOSPERMINE; DELTA CONICEINE; DESACETOXYSLAFRAMINE; INDOLIZIDINE ALKALOID; INDOLIZIDINE DERIVATIVE; INDOLIZINE DERIVATIVE; SERINE; SLAFRAMINE; SWAINSONINE; UNCLASSIFIED DRUG;

ANTIVIRAL ACTIVITY; ARTICLE; CHIRALITY; CYCLIZATION; DRUG STRUCTURE; DRUG SYNTHESIS; HUMAN IMMUNODEFICIENCY VIRUS; HYDROGENATION; REACTION ANALYSIS; STEREOCHEMISTRY; STRUCTURE ACTIVITY RELATION;

EID: 0033588329     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo9908546     Document Type: Article

References (94)

1. Taken in part from the Ph.D. Thesis of J. W. Christensen, North Dakota State University, 1994.
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15. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
16. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
17. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
18. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
19. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
20. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
21. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
22. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
23. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
24. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
25. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
26. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
27. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
28. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
29. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
30. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
31. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
32. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
33. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez- Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
34. Coniceine Isolation: Roberts, M. F.; Brown, R. T. Phytochemistry 1981, 20, 447. Racemic synthesis: (a) Martin-Lopez, M. J.; Bermejo-Gonzalez, F. Tetrahedron Lett. 1994, 35, 4235. (b) Jung, M. E.; Choi, Y. M. J. Org. Chem. 1991, 56, 6729. (c) Green, D. L. C.; Thompson, C. M. Tetrahedron Lett. 1991, 32, 5051. (d) Garst, M. E.; Bonfiglio, J. N.; Marks, J. J. Org. Chem. 1982, 47, 1494. (e) Garst, M. E.; Bonfiglio, J. N. Tetrahedron Lett. 1981, 2075. (f) Khatri, N. A.; Schmitthenner, H. F.; Shringarpure, J.; Weinreb, S. M. J. Am. Chem. Soc. 1981, 103, 6387. (g) Schell, F. M.; Ganguly, R. N. J. Org. Chem. 1980, 45, 4069. (h) Munchof, M. J.; Meyers, A. I. J. Org. Chem. 1995, 60, 7084. (i) Sato, Y.; Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron 1994, 50, 371. (j) Nukui, S.; Sodeoka, M.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 4965. (k) Waldmann, H.; Braun, M. J. Org. Chem. 1992, 57, 4444. (l) Waldmann, H.; Braun, M. Gazz. Chim. Ital. 1991, 121, 277. (m) Pearson, W. H.; Lin, K.-C. Tetrahedron Lett. 1990, 31, 7571. (n) Danishefsky, S.; Taniyama, E.; Webb II, R. R. Tetrahedron Lett. 1983, 24, 11. (o) Branchaud, B. P. J. Org. Chem. 1983, 48, 3538. (p) Arisawa, M.; Takezawa, E.; Niishida, A.; Mori, M.; Nakagawa, M. Synlett 1997, 1179. (q) Takahata, H.; Kubota, M.; Momose, T. Tetrahedron: Asymmetry 1996, 7, 3047. (r) De Kimpe, N.; Stanoeva, E.; Kulinkovich, O. Org. Prep. Proced. Int. 1995, 27, 674. (s) Sánchez-Sancho, F.; Herradón, B. Tetrahedron: Asymmetry 1998, 9, 1951.
35. 1-Hydroxyindolizidine synthesis: (a) Takahata, H.; Banba, Y.; Momose, T. Tetrahedron: Asymmetry 1990, 1, 763. (b) Takahata, H.; Tajima, M.; Banba, Y.; Momose, T. Chem. Pharm. Bull. 1989, 37, 2550. (c) ref 3 a and b. (d) Green, D. L. C.; Kiddle, J. J.; Thompson, C. M. Tetrahedron 1997, 51, 2865.
36. 1-Hydroxyindolizidine synthesis: (a) Takahata, H.; Banba, Y.; Momose, T. Tetrahedron: Asymmetry 1990, 1, 763. (b) Takahata, H.; Tajima, M.; Banba, Y.; Momose, T. Chem. Pharm. Bull. 1989, 37, 2550. (c) ref 3 a and b. (d) Green, D. L. C.; Kiddle, J. J.; Thompson, C. M. Tetrahedron 1997, 51, 2865.
37. 1-Hydroxyindolizidine synthesis: (a) Takahata, H.; Banba, Y.; Momose, T. Tetrahedron: Asymmetry 1990, 1, 763. (b) Takahata, H.; Tajima, M.; Banba, Y.; Momose, T. Chem. Pharm. Bull. 1989, 37, 2550. (c) ref 3 a and b. (d) Green, D. L. C.; Kiddle, J. J.; Thompson, C. M. Tetrahedron 1997, 51, 2865.
38. 1-Hydroxyindolizidine synthesis: (a) Takahata, H.; Banba, Y.; Momose, T. Tetrahedron: Asymmetry 1990, 1, 763. (b) Takahata, H.; Tajima, M.; Banba, Y.; Momose, T. Chem. Pharm. Bull. 1989, 37, 2550. (c) ref 3 a and b. (d) Green, D. L. C.; Kiddle, J. J.; Thompson, C. M. Tetrahedron 1997, 51, 2865.
39. Racemic slaframine synthesis: (a) Wasserman, H. H.; Vu, C. B. Tetrahedron Lett. 1994, 35, 9779. (b) Dartmann, M.; Flitsch, W.; Krebs, B.; Pandl, K.; Westfechtel, A. Liebigs Ann. Chem. 1988, 695. (c) Schneider, M. J.; Harris, T. M. J. Org. Chem. 1984, 49, 20, 3681. (d) Gobao, R. A.; Bremmer, M. L.; Weinreb, S. M. J. Am. Chem. Soc. 1982, 104, 7065.
40. Racemic slaframine synthesis: (a) Wasserman, H. H.; Vu, C. B. Tetrahedron Lett. 1994, 35, 9779. (b) Dartmann, M.; Flitsch, W.; Krebs, B.; Pandl, K.; Westfechtel, A. Liebigs Ann. Chem. 1988, 695. (c) Schneider, M. J.; Harris, T. M. J. Org. Chem. 1984, 49, 20, 3681. (d) Gobao, R. A.; Bremmer, M. L.; Weinreb, S. M. J. Am. Chem. Soc. 1982, 104, 7065.
41. Racemic slaframine synthesis: (a) Wasserman, H. H.; Vu, C. B. Tetrahedron Lett. 1994, 35, 9779. (b) Dartmann, M.; Flitsch, W.; Krebs, B.; Pandl, K.; Westfechtel, A. Liebigs Ann. Chem. 1988, 695. (c) Schneider, M. J.; Harris, T. M. J. Org. Chem. 1984, 49, 20, 3681. (d) Gobao, R. A.; Bremmer, M. L.; Weinreb, S. M. J. Am. Chem. Soc. 1982, 104, 7065.
42. Racemic slaframine synthesis: (a) Wasserman, H. H.; Vu, C. B. Tetrahedron Lett. 1994, 35, 9779. (b) Dartmann, M.; Flitsch, W.; Krebs, B.; Pandl, K.; Westfechtel, A. Liebigs Ann. Chem. 1988, 695. (c) Schneider, M. J.; Harris, T. M. J. Org. Chem. 1984, 49, 20, 3681. (d) Gobao, R. A.; Bremmer, M. L.; Weinreb, S. M. J. Am. Chem. Soc. 1982, 104, 7065.
43. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
44. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
45. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
46. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
47. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
48. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
49. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
50. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
51. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
52. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
53. Enantioselective slaframine synthesis: (a) Knight, D. W.; Sibley, A. W. J. Chem. Soc., Perkin Trans. 1 1997, 2179. (b) Szeto, P.; Lathbury, D. C.; Gallagher, T. Tetrahedron Lett. 1995, 36, 6957. (c) Gmeiner, P.; Junge, D.; Kaertner, A. J. Org. Chem. 1994, 59, 6766. (d) Hua, D. H.; Park, J.-G.; Katsuhira, T.; Bharathi, S. N. J. Org. Chem. 1993, 58, 2144. (e) Knight, D. W.; Sibley, W. A. Tetrahedron Lett. 1993, 34, 6607. (f) Knapp, S.; Gibson, F. S. J. Org. Chem. 1992, 57, 4802. (g) Pearson, W. H.; Bergmeier, S. C.; Williams, J. P. J. Org. Chem. 1992, 57, 3977. (h) Pearson, W. H.; Bergmeier, S. C. J. Org. Chem. 1991, 56, 1976. (i) Choi, J.-R.; Han, S.; Cha, J. K. Tetrahedron Lett. 1991, 32, 6469. (j) Kang, S. H.; Kim, J. S.; Youn, J.-H. Tetrahedron Lett. 1998, 39, 9047. (k) Carretero, J. C.; Arrayás, R. G. Synlett 1999, 49.
54. For preliminary work in this area see: Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1990, 31, 5689.
55. Sibi, M. P.; Christensen, J. W.; Li, B.; Renhowe, P. J. Org. Chem. 1992, 57, 4329.
56. The prolinal is stable to fast flash column chromatographic purification and is optically stable to freezer storage for up to a week. Generally it was used without purification.
57. Kunz, H. Justus Liebig Ann. Chem. 1973, 2001.
58. For a general discussion on oxido ylides see: Maryanoff, B. E.; Reitz, A. B.; Duhl-Emswiler, B. A. J. Am. Chem. Soc. 1985, 107, 217.
59. Ringdahl, B.; Pinder, A. R.; Periera, W. E.; Oppenheimer, N. J., Jr.; Craig, J. C. J. Chem. Soc., Perkin Trans. 1 1984, 1.
60. (a) Sheehan, J. C.; Whitney, J. G. J. Am. Chem. Soc. 1962, 84, 3980.
61. (b) Ko, C.; Johnson, L. D.; Priest, R. E. Biochim. Biophys. Acta 1979, 581, 252.
62. Prepared in three steps with 25% overall yield following the procedure of Blake, J.; Wilson, C. D.; Rapoport, H. J. Am. Chem. Soc. 1964, 86, 5293.
63. Feil, P. D.; Vercellotti, J. R. Carbohydr. Res. 1973, 31, 311.
64. For an alternative regioselective Dieckmann condensation proceeding in higher overall yields see: Sibi, M. P.; Christensen, J. W.; Kim, S.-G.; Eggen, M.; Stessman, C.; Oien, L. Tetrahedron Lett. 1995, 36, 6209.
65. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
66. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
67. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
68. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
69. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
70. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
71. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
72. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
73. Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Chem. Commun. 1988, 509. This procedure utilizes BOC-3-ketoproline ethyl ester as the substrate. For a detailed experimental account and characterization data see ref 13a. For selected and recent syntheses of syn-3-hydroxyprolines see: (a) Sundram, H.; Golebiowski, A.; Johnson, C. R. Tetrahedron Lett. 1993, 35, 6975. (b) Knight, D. W.; Sibley, A. W. Tetrahedron Lett. 1993, 34, 6607. (c) Cooper, J.; Gallagher, P. T.; Knight, D. W. J. Chem. Soc., Perkin Trans. 1 1993, 1313. (d) Jurczak, J.; Prokopowicz, P.; Golebiowski, A. Tetrahedron Lett. 1993, 34, 7107. (e) Sibi, M. P.; Christensen, J. W. Tetrahedron Lett. 1995, 36, 6213. (f) Gotschi, E.; Jenny, C.-J.; Reindl, P.; Ricklin, F. Helv. Chim. Acta 1996, 79, 2219. (g) Mulzer, J.; Meier, A.; Luger, P. J. Org. Chem. 1996, 61, 566. (i) Dell'Uomo, N.; Di Giovanni, M. C.; Misiti, D.; Zappia, G.; Monache, G. D. Tetrahedron: Asymmetry 1996, 7, 181.
74. The optical purity and stereochemistry were established by conversion to the known N-BOC-protected proline and by comparison of spectral data and rotation values. Additionally, the optical purity was established by HPLC analysis of the 3,5-dinitrobenzoates on a Pirkle column and by MPTA derivatives.
75. Nakamura, K.; Kawai, Y.; Oka, S.; Ohno, A. Tetrahedron Lett. 1989, 30, 2245 and references therein.
76. One explanation for the low yield is the observed migration of the TBDMS protecting group to the alkoxide oxygen during the Wittig reaction.
77. (a) Harris, C. M.; Harris, T. M. Tetrahedron Lett. 1987, 28, 2559.
78. (b) Takahata, H.; Tajima, M.; Banba, Y.; Mosome, T. Chem. Pharm. Bull. Jpn. 1989, 37, 2550 and references therein.
79. Sibi, M. P.; Renhowe, P. Tetrahedron Lett. 1990, 31, 7407.
80. 6 indicate that it is instead the cis isomer that is formed. See the Experimental Section for coupling constants indicative of the cis geometry.
81. Rawal, V. H.; Cava, M. P. Tetrahedron Lett. 1986, 26, 6141.
82. For reports on intermolecular β-functionalization of cyclic sulfamidates see: (a) Baldwin, J. E.; Spivey, A. C.; Schofield, C. J. Tetrahedron: Asymmetry 1990, 1, 881. (b) Alker, D.; Doyle, K. J.; Harwood: L. M.; McGregor, A. Tetrahedron: Asymmetry 1990, 1, 877. (c) Zubovics, Z.; Tody, L.; Varro, A.; Rabloczky, G.; Kurthy, P.; Duortsak, P.; Jerkovich, G.; Tomori, E. J. Med. Chem. 1986, 21, 370. (d) White, G. J.; Garst, M. E. J. Org. Chem. 1991, 56, 3177. (e) Gautun, H. S. H.; Carlsen, P. H. J. Tetrahedron: Asymmetry 1995, 6, 1667.
83. For reports on intermolecular β-functionalization of cyclic sulfamidates see: (a) Baldwin, J. E.; Spivey, A. C.; Schofield, C. J. Tetrahedron: Asymmetry 1990, 1, 881. (b) Alker, D.; Doyle, K. J.; Harwood: L. M.; McGregor, A. Tetrahedron: Asymmetry 1990, 1, 877. (c) Zubovics, Z.; Tody, L.; Varro, A.; Rabloczky, G.; Kurthy, P.; Duortsak, P.; Jerkovich, G.; Tomori, E. J. Med. Chem. 1986, 21, 370. (d) White, G. J.; Garst, M. E. J. Org. Chem. 1991, 56, 3177. (e) Gautun, H. S. H.; Carlsen, P. H. J. Tetrahedron: Asymmetry 1995, 6, 1667.
84. For reports on intermolecular β-functionalization of cyclic sulfamidates see: (a) Baldwin, J. E.; Spivey, A. C.; Schofield, C. J. Tetrahedron: Asymmetry 1990, 1, 881. (b) Alker, D.; Doyle, K. J.; Harwood: L. M.; McGregor, A. Tetrahedron: Asymmetry 1990, 1, 877. (c) Zubovics, Z.; Tody, L.; Varro, A.; Rabloczky, G.; Kurthy, P.; Duortsak, P.; Jerkovich, G.; Tomori, E. J. Med. Chem. 1986, 21, 370. (d) White, G. J.; Garst, M. E. J. Org. Chem. 1991, 56, 3177. (e) Gautun, H. S. H.; Carlsen, P. H. J. Tetrahedron: Asymmetry 1995, 6, 1667.
85. For reports on intermolecular β-functionalization of cyclic sulfamidates see: (a) Baldwin, J. E.; Spivey, A. C.; Schofield, C. J. Tetrahedron: Asymmetry 1990, 1, 881. (b) Alker, D.; Doyle, K. J.; Harwood: L. M.; McGregor, A. Tetrahedron: Asymmetry 1990, 1, 877. (c) Zubovics, Z.; Tody, L.; Varro, A.; Rabloczky, G.; Kurthy, P.; Duortsak, P.; Jerkovich, G.; Tomori, E. J. Med. Chem. 1986, 21, 370. (d) White, G. J.; Garst, M. E. J. Org. Chem. 1991, 56, 3177. (e) Gautun, H. S. H.; Carlsen, P. H. J. Tetrahedron: Asymmetry 1995, 6, 1667.
86. For reports on intermolecular β-functionalization of cyclic sulfamidates see: (a) Baldwin, J. E.; Spivey, A. C.; Schofield, C. J. Tetrahedron: Asymmetry 1990, 1, 881. (b) Alker, D.; Doyle, K. J.; Harwood: L. M.; McGregor, A. Tetrahedron: Asymmetry 1990, 1, 877. (c) Zubovics, Z.; Tody, L.; Varro, A.; Rabloczky, G.; Kurthy, P.; Duortsak, P.; Jerkovich, G.; Tomori, E. J. Med. Chem. 1986, 21, 370. (d) White, G. J.; Garst, M. E. J. Org. Chem. 1991, 56, 3177. (e) Gautun, H. S. H.; Carlsen, P. H. J. Tetrahedron: Asymmetry 1995, 6, 1667.
87. Reference 13h. We thank Professor Pearson, University of Michigan, for providing the spectra and an authentic sample of slaframine.
88. Arguably, the observed change in mass could have only been from evaporation of substrate. To disprove this argument, a thermo-gravimetric analysis (TGA) was run on the tert-butyldimethylsilyloxy (OTBDMS) derivative 35. If evaporation were the phenomenon being observed, this compound should exhibit a higher value for the first derivative of mass change because of its higher boiling point. When a TGA was run on this derivative, it was found that the temperature of the first-derivative maximum is similar to that of the parent, so the observed mass change must be a result of cyclization and subsequent evaporation of product.
89. Poindexter, G. S.; Owens, D. A.; Dolan, P. L.; Woo, E. J. Org. Chem. 1992, 57, 6257.
90. The corresponding 4-OSEM [2-(trimethylsilyl)ethoxymethyl] aldehyde gave only a 19% yield of the olefin [the (Z)-isomer only].
91. A working hypothesis for the variation in chemical yield with changes in the protecting group is as follows. Chelation of a lithium counterion with the aldehyde oxygen and the BOC group or the 3-oxygen substituent could account for the differences in reactivity. Of the two different protecting groups, the bulky TBDMS group precludes lithium complexation with its oxygen whereas the smaller OSEM forms stable lithium complexes. Although the BOC group is sterically demanding, the carbonyl oxygen is still quite open for intramolecular complexation. Lithium complexation holds the aldehyde in various conformations that either open the carbonyl for nucleophilic attack by the ylide or block the incoming ylide, resulting in lowered chemical yields when the approach is
92. A working hypothesis for the variation in chemical yield with changes in the protecting group is as follows. Chelation of a lithium counterion with the aldehyde oxygen and the BOC group or the 3-oxygen substituent could account for the differences in reactivity. Of the two different protecting groups, the bulky TBDMS group precludes lithium complexation with its oxygen whereas the smaller OSEM forms stable lithium complexes. Although the BOC group is sterically demanding, the carbonyl oxygen is still quite open for intramolecular complexation. Lithium complexation holds the aldehyde in various conformations that either open the carbonyl for nucleophilic attack by the ylide or block the incoming ylide, resulting in lowered chemical yields when the approach is disfavored. For comprehensive reviews on oxido and semistabilized ylides see:: Vedejs, E.; Peterson. M. J. In Topics in Stereochemistry; Eliel, E. L., Wilen, S. H., Eds.; Wiley: New York, 1994; Vol. 21, Chapter 1. Maryanoff, B. E.; Reitz, A. B. Chem. Rev. 1989, 89, 863; ref 18.
93. For details and a discussion on the origins of the selectivity see: Sibi, M. P.; Rutherford, D. R.; Renhowe, P. A.; Li, B. J. Am. Chem. Soc., in press.
94. Lipshutz, B. H.; Pegram, J. J. Tetrahedron Lett. 1980, 21, 3343.