The N-Acyloxyiminium Ion Aza-Prins Route to Octahydroindoles: Total Synthesis and Structural Confirmation of the Antithrombotic Marine Natural Product Oscillarin

Journal of the American Chemical Society

Volumn 126, Issue 19, 2004, Pages 6064-6071

  Hanessian, Stephen ^a   Tremblay, Martin ^a   Petersen, Jens F W ^b  

^a UNIVERSITÉ DE MONTRÉAL   (Canada)

^b ASTRAZENECA R AND D   (Sweden)

Author keywords

[No Author keywords available]

Indexed keywords

CRYSTAL STRUCTURE; ENZYME INHIBITION; STEREOCHEMISTRY; SYNTHESIS (CHEMICAL);

MARINE NATURAL PRODUCTS; OSCILLARIN; SECONDARY CARBOCATION; X-RAY STRUCTURES;

ORGANIC COMPOUNDS;

ALKENE; ALKENE DERIVATIVE; ANTICOAGULANT AGENT; CARBOXYLIC ACID DERIVATIVE; CHLORINE DERIVATIVE; IMINIUM ION; INDOLE DERIVATIVE; ION; N ACYLOXYIMINIUM ION; NATURAL PRODUCT; OCTAHYDROINDOLE 2 CARBOXYLIC ACID DERIVATIVE; OCTAHYDROINDOLE DERIVATIVE; OSCILLARIN; THROMBIN DERIVATIVE; UNCLASSIFIED DRUG;

ARTICLE; COMPLEX FORMATION; CRYSTAL STRUCTURE; CYCLIZATION; DRUG ISOLATION; DRUG STRUCTURE; ENANTIOMER; STEREOCHEMISTRY; STRUCTURE ANALYSIS; VALIDATION PROCESS; X RAY ANALYSIS;

ALKYLATION; AZA COMPOUNDS; BIOLOGICAL FACTORS; CRYSTALLOGRAPHY, X-RAY; CYCLIZATION; FIBRINOLYTIC AGENTS; INDICATORS AND REAGENTS; MAGNETIC RESONANCE SPECTROSCOPY; MARINE BIOLOGY; MODELS, MOLECULAR; MOLECULAR CONFORMATION; OLIGOPEPTIDES;

EID: 2442490039     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja030669g     Document Type: Article

References (140)

1. (a) Murakami, M.; Okita, Y.; Matsuda, H.; Okino, H.; Yamaguchi, K.; Tetrahedron Lett. 1994, 35, 3129.
2. (b) Murakami, M.; Ishida, K.; Okino, T.; Okita, Y.; Matsuda, H.; Yamaguchi, K. Tetrahedron Lett. 1995, 36, 2785.
3. (c) Matsuda, H.; Okino, T.; Murakami, M.; Yamaguchi, K. Tetrahedron 1996, 52, 14501.
4. For recent reviews, see (a) Leusch, H.; Harrigan, G. G.; Goetz, G.; Horgen, F. D. Curr. Med. Chem. 2002, 9, 179.
5. (b) Burja, A. M.; Banaigs, B.; Abou-Mansour, E.; Burgess, J.-G.; Wright, P. C. Tetrahedron 2001, 57, 9347.
6. (c) For a recent review, see Shiori, T.; Hamada, Y. Synlett 2001, 184.
7. (d) Lewis, J. R. Nat. Prod. Rep. 1998, 417.
8. (e) Namikoshi, M.; Rinehart, K. L. J. Indust. Microbiol. 1996, 17, 373.
9. (f) Rinehart, K. L.; Namikoshi, M.; Choi, B. W. J. Appl. Phycol. 1994, 6, 159.
10. Rios Steiner, J. L.; Murakami, M.; Tulinsky, A. J. Am. Chem. Soc. 1998, 120, 597.
11. Wipf, P.; Methot, J.-L. Org. Lett. 2000, 2, 4213.
12. (a) Valls, N.; López-Canet, M.; Vallribera, M.; Bonjoch, J. J. Am. Chem. Soc. 2000, 122, 11248.
13. (b) Valls, N.; López-Canet, M.; Vallribera, M.; Bonjoch, J. Chem. Eur. J. 2001, 7, 3446.
14. (a) Sandler, B.; Murakami, M.; Clardy, J. J. Am. Chem. Soc. 1998, 120, 595.
15. (b) Kodani, S.; Ishida, K.; Murakami, M. J. Nat. Prod. 1998, 61, 1040.
16. (c) Ishida, K.; Okita, Y.; Matsuda, H.; Okino, T.; Murakami, M. Tetrohedron 1999, 55, 10971.
17. (d) Ishida, R.; Murakami, M. J. Org. Chem. 2000, 65, 5898.
18. (e) Ishida, K.; Kato, T.; Murakami, M.; Watanabe, M.; Watanabe, M. F. Tetrahedron 2000, 56, 8643.
19. (a) Fujii, K.; Sivonen, K.; Adachi, K.; Nagachi, K.; Shimizo, Y.; Sano, H.; Hirayama, K.; Suzuki, M.; Harada, K. Tetrahedron Lett. 1997, 38, 5529.
20. (b) Banker, R.; Carmeli, S. Tetrahedron 1999, 55, 10835.
21. (a) Aeruginosin 298A: Ohshima, T.; Gnanadesikan, V.; Shibughushi, T.; Fukuta, Y.; Nemoto, T.; Shibasaki, M. J. Am. Chem. Soc. 2003, 125, 11206.
22. (b) Aeruginosin E1461: Valls, M.; Vallribera, M.; Carmeli, S.; Bonjoch, J. Org. Lett. 2003, 5, 447.
23. (c) Valls, N.; Vallribera, M.; López-Canet, M.; Bonjoch, J. J. Org. Chem. 2002, 67, 4945.
24. Hanessian, S.; Margarita, R.; Hall, A.; Johnstone, S.; Tremblay, M.; Parlanti, L. J. Am. Chem. Soc. 2002, 124, 13342.
25. Carroll, A. R.; Pierens, G.; Fechner, G.; de Almeidaleona, P.; Ngo, A.; Simpson, M.; Hooper, J. N. A.; Böstrom, S. L.; Musil, D.; Quinn, R. J. J. Am. Chem. Soc. 2002, 124, 13340.
26. For selected reviews on thrombin inhibitors, see (a) Sanderson, P. E. J. ; Nayler-Olson, A. M. Curr. Med. Chem. 1998, 5, 289.
27. (b) Ripka, W. E. Curr. Opin. Chem. Biol. 1997, 1, 242.
28. (c) Pfau, R. Curr. Opin. Drug Discovery 2003, 6, 437.
29. (a) Steinmetz, T.; Hauptman, J.; Stürzbecher, J. Exp. Opin. Invest Drugs 2000, 10, 845.
30. (b) Lolman, R. W.; Marder, V. J.; Salzman, E.; Hirsch, W. In Hemoslasis and Thrombosis: Basic Principles and Clinical Practice, 3rd ed.; Colman, R. W., Hirsch, W., Marder, V. J., Salzman, E. W., Eds.; Lippinott, J. B: Philadelphia, PA, 1994; p 3.
31. A chlorinated dysinosin-like product has been recently isolated from Dysidea sp. sponges: Goetz, G. H.; Harrigan, G. G.; Likos, J. J.; Kasten, T. P. PCT WO 03/051831; Chem. Abst. 2003, 139, 47155.
32. Engh, R.; Konetschny-Rapp, S.; Krell, H.-W.; Martin, U.; Tsaklakidis, C. PCT WO97/21725; Chem. Abst. 1997, 127, 122002.
33. Shin, H. J.; Matsuda, M.; Murakami, M.; Yamaguchi, K. J. Org. Chem. 1997, 62, 1810.
34. Valls, N.; Vallribera, M.; Font-Bardía; Solans, X.; Bonjoch, J. Tetrahedron: Asymmetry 2003, 14, 1241.
35. Konetschny-Rapp, S.; Krell, H.-W.; Martin, U. PCT WO 96/11941; Chem. Abst. 1996, 124, 315175.
36. (a) Wipf, P.; Kim, Y.; Goustein, D. M. J. Am. Chem. Soc. 1995, 117, 1106.
37. (b) Wipf, P.; Maresko, D. A. Tetrahedron Lett. 2000, 41, 4723. Wipf, P.; Li, W. J. Org. Chem. 1999, 64, 4576.
38. (b) Wipf, P.; Maresko, D. A. Tetrahedron Lett. 2000, 41, 4723. Wipf, P.; Li, W. J. Org. Chem. 1999, 64, 4576.
39. (a) Bonjoch, J., Catena, J.; Isabal, E.; López-Canet, M.; Valls, N. Tetrahedron: Asymmetry 1996, 7, 1899.
40. (b) Bonjoch, J.; Catena, J.; Valls, N. J. Org. Chem. 1996, 61, 7106.
41. (a) Belvisi, L.; Colombo, L.; DiGiacomo, M.; Manzoni, L.; Vodopivec, B.; Scolastico, C. Tetrahedron 2001, 57, 6463.
42. (b) Toyooka, N.; Okumura, M.; Himiyama, T.; Nakazawa, A.; Nemoto, H. Synlett 2003, 55.
43. For excellent general reviews on N-acyliminium ion chemistry, see (a) Speckamp, W. N.; Moolenaar, M. J. Tetrahedron 2000, 56, 3817.
44. (b) Hiemstra, H.; Speckamp, W. N. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Heathcock, C. H., Eds.; Pergamon: New York, 1991; 2, 1047.
45. (c) Speckamp, W. N.; Hiemstra, H. Tetrahedron 1985, 41, 4367.
46. (d) Speckamp, W. N. Rec. Trav. Chim. Pays-Bas 1981, 100, 345. The term "N-acyloxyiminium ion aza-Prins cyclization" is used in analogy to the Prins or oxonia-Prins cyclizations (see refs 23, 39, 40). In the present examples, an unactivated terminal olefin is engaged in intramolecular C-C bond formation with an endocyclic N-acyloxyiminium ion via a cationic intermediate that is trapped by halide ion. For the use of aza-Prins in a different context, see Nicolaou, K.; Snyder, S. A.; Montagnon, T.; Vassilikogiannakis, G. Angew Chem. Ind. Ed. 2002, 41, 1668 as cited on p 1680 in relation to the "Diels-Alder/aza-Prins cascade" during the total synthesis of methyl homosecodaphniphylate, Ruggeri, R. B.; Hansen, M. M.; Heathcock C. H. J. Am. Chem. Soc. 1988, 110, 8734. Strictly speaking, the term azonia-Prins rather than aza-Prins should be used (see IUPAC rules of nomenclature, 1993; Heterocyclic Systems Rule B-6. Cationic Hetero Atoms). In the present case, however, the mention of N-acyloxyiminium ion already implies the involvement of a charged nitrogen.
47. (d) Speckamp, W. N. Rec. Trav. Chim. Pays-Bas 1981, 100, 345. The term "N-acyloxyiminium ion aza-Prins cyclization" is used in analogy to the Prins or oxonia-Prins cyclizations (see refs 23, 39, 40). In the present examples, an unactivated terminal olefin is engaged in intramolecular C-C bond formation with an endocyclic N-acyloxyiminium ion via a cationic intermediate that is trapped by halide ion. For the use of aza-Prins in a different context, see Nicolaou, K.; Snyder, S. A.; Montagnon, T.; Vassilikogiannakis, G. Angew Chem. Ind. Ed. 2002, 41, 1668 as cited on p 1680 in relation to the "Diels-Alder/aza-Prins cascade" during the total synthesis of methyl homosecodaphniphylate, Ruggeri, R. B.; Hansen, M. M.; Heathcock C. H. J. Am. Chem. Soc. 1988, 110, 8734. Strictly speaking, the term azonia-Prins rather than aza-Prins should be used (see IUPAC rules of nomenclature, 1993; Heterocyclic Systems Rule B-6. Cationic Hetero Atoms). In the present case, however, the mention of N-acyloxyiminium ion already implies the involvement of a charged nitrogen.
48. (d) Speckamp, W. N. Rec. Trav. Chim. Pays-Bas 1981, 100, 345. The term "N-acyloxyiminium ion aza-Prins cyclization" is used in analogy to the Prins or oxonia-Prins cyclizations (see refs 23, 39, 40). In the present examples, an unactivated terminal olefin is engaged in intramolecular C-C bond formation with an endocyclic N-acyloxyiminium ion via a cationic intermediate that is trapped by halide ion. For the use of aza-Prins in a different context, see Nicolaou, K.; Snyder, S. A.; Montagnon, T.; Vassilikogiannakis, G. Angew Chem. Ind. Ed. 2002, 41, 1668 as cited on p 1680 in relation to the "Diels-Alder/aza-Prins cascade" during the total synthesis of methyl homosecodaphniphylate, Ruggeri, R. B.; Hansen, M. M.; Heathcock C. H. J. Am. Chem. Soc. 1988, 110, 8734. Strictly speaking, the term azonia-Prins rather than aza-Prins should be used (see IUPAC rules of nomenclature, 1993; Heterocyclic Systems Rule B-6. Cationic Hetero Atoms). In the present case, however, the mention of N-acyloxyiminium ion already implies the involvement of a charged nitrogen.
49. Hanessian, S.; Margarita, R. Tetrahedron Lett. 1998, 39, 5887.
50. 4 in a Prins cyclization of an oxocarbenium ion, see Marumoto, S.; Saber, J. J.; Vitale, J. P.; Rychnovsky, S. D. Org. Lett. 2002, 4, 3919.
51. See Supporting Information for details.
52. (a) Feichtinger, K.; Sings, H. L.; Baker, T. J.; Matthews, K.; Goodman, M. J. Org. Chem. 1998, 63, 8432.
53. (b) McManus, J. C.; Genski, T.; Carey, J. S.; Taylor, R. J. K. Synlett 2003, 369.
54. Vaultier, M.; Knouzi, N.; Carrie, R. Tetrahedron Lett. 1983, 24, 763.
55. Nilsson, T.; Sjoling-Ericksson, A.; Deinum, J. J. Enzyme Inhibition 1998, 13, 11.
56. Skrypczak-Jankum, E.; Carperus, V. E.; Ravichandran, K. G.; Tulinsky, A. ; Westbrook, M.; Maraganore, J. M. J. Mol. Biol 1991, 221, 1379.
57. (a) Overman, L. E. Acc. Chem. Res. 1992, 25, 352.
58. (b) Overman, L. E.; Ricca, D. J. In Comprehensive Organic Synthesis; Trost, B. M., Ed.; Pergamon: London, 1991; 2, 1007.
59. (c) Franklin, A. S.; Overman, L. E.; Chem. Rev. 1996, 96, 505.
60. See, for example, (a) Stevens, R. V.; Lee, A. W. M. J. Am. Chem. Soc. 1979, 101, 7032.
61. (b) Wenkert, E.; Chang, C.-J.; Chawla, H. P. S.; Cochran, D. W.; Hagaman, E. W.; King, J. C.; Orito, K. J. Am. Chem. Soc. 1976, 98, 3645.
62. (c) Ziegler, F. E.; Spitzner, E. B. J. Am Chem. Soc. 1973, 95, 7146.
63. (d) Overman, L. E.; Freerks, R. F. J. Org. Chem. 1981, 46, 2833.
64. (e) Overman, L. E.; Fukaya, C. J. Am Chem. Soc. 1980, 102, 1454.
65. (f) Heathcock, C. H.; Kleinman, E. F.; Binkley, E. S. J. Am. Chem. Soc. 1982, 104, 1054.
66. See, for example, (a) Hart, D. J. J. Am. Chem. Soc. 1980, 102, 397.
67. (b) Overman, L. E.; Lesuisse, D.; Hashimoto, M. J. Am. Chem. Soc. 1983, 105, 5373.
68. (c) Overman, L. E.; Fukaya, C. J. Am. Chem. Soc. 1980, 102, 1454.
69. (d) Chow, Y. L.; Colón, C. J.; Tam, J. N. S. Can. J. Chem. 1968, 46, 2821.
70. (e) Fraser, R. R.; Grindley, T. B. Tetrahedron Len. 1974, 416.
71. (f) Scott, J. W.; Durham, L. J.; DeJongh, H. A. P.; Burkhardt, V.; Johnson, W. S. Tetrahedron Lett. 1967, 2381.
72. (g) Quick, J.; Mondello, C.; Humora, M.; Brennan, T. J. Org. Chem. 1978, 43, 2705.
73. (h) Brown, J. D.; Foley, M. A.; Comins, D. L. J. Am. Chem. Soc. 1988, 110, 7445.
74. (i) Beak, P.; Zajdel, W. J. J. Am. Chem. Soc. 1984, 106, 1010. For reviews, see Hoffmann, R. W. Chem. Rev. 1989, 89, 1841. Johnson, F. Chem. Rev. 1968, 68, 375.
75. (i) Beak, P.; Zajdel, W. J. J. Am. Chem. Soc. 1984, 106, 1010. For reviews, see Hoffmann, R. W. Chem. Rev. 1989, 89, 1841. Johnson, F. Chem. Rev. 1968, 68, 375.
76. (i) Beak, P.; Zajdel, W. J. J. Am. Chem. Soc. 1984, 106, 1010. For reviews, see Hoffmann, R. W. Chem. Rev. 1989, 89, 1841. Johnson, F. Chem. Rev. 1968, 68, 375.
77. For the synthesis of Lewis acid catalyzed halogenated azacyclic systems, see (a) Udding, J. H.; Tuijp, C. J. M.; Hiemstra, H.; Speckamp, W. N. J. Chem. Soc., Perkin Trans. 2 1992, 857.
78. (b) Rutjes, F. P. J. T.; Hiemstra, H.; Pirrung, F. O. H.; Speckamp, W. N. Tetrahedron 1993, 49, 10027.
79. (c) Li, W.; Hanau, C. E.; d'Avignon, A.; Moeller, K. D. J. Org. Chem. 1995, 60, 8155.
80. For solvolytic reactions with formic acid see (d) Demailly, G.; Solladié, G. J. Org. Chem. 1981, 36, 3102.
81. (e) Hart, D. J.; Kanai, K.-I. J. Am. Chem. Soc. 1983, 105, 1255.
82. (f) Hart, D. J.; Hong, W. P. J. Org. Chem. 1985, 50, 3670.
83. (f) Cannizzo, L. F.; Grubbs, R. H. J. Org. Chem. 1985, 50, 2316.
84. (g) Brosius, A. D.; Overman, L. E. J. Org. Chem. 1997, 62, 440.
85. (h) Frank, K. E.; Aubé, J. Tetrahedron Lett. 1998, 39, 7239.
86. (i) Schoemaker, H. E.; Dijkink, J.; Speckamp, W. N. Tetrahedron 1978, 34, 163.
87. (j) Dijkink, J.; Speckamp, W. N. Tetrahedron 1978, 34, 173.
88. For ene-type reactions, see (k) Ruggeri, R. B.; Hansen, H. M.; Heathcock, C. H. J. Am. Chem. Soc. 1988, 110, 8734.
89. (l) Tanner, D.; Hagberg, L. Tetrahedron 1998, 54, 7907.
90. For an example of ester participation, see (m) Endoma, M. A.; Butora, G. ; Claeboe, C. D.; Hudlicky, T.; Abboud, K. A. Tetrahedron Lett. 1997, 38, 8833.
91. Fisher, M. J.; Overman, L. E. J. Org. Chem. 1990, 55, 1447.
92. For examples involving solvolysis with formic acid, see (a) Oostveen, A. R. C.; de Boer, J. J. L; Speckamp, W. N. Heterocycles 1977, 7, 171.
93. (b) Schoemaker, H. E.; Kruk, C.; Speckamp, W. N. Tetrahedron Lett. 1979, 2437.
94. For Lewis acids and alkene tethers see (c) Melching, K. H.; Hiemstra, H. ; Klaver, W. J.; Speckamp, W. N. Tetrahedron Lett. 1986, 27, 4799.
95. (d) Esch, P. M.; Boska, I. M.; Hiemstra, H.; de Boer, R. F.; Speckamp, W. N. Tetrahedron, 1991, 47, 4039.
96. For solvolysis of allenic or acetylenic tethers see (e) Beyersbergen van Henegouwen, W. G.; Hiemstra, H. J. Org. Chem. 1997, 62, 8862.
97. For applications to β-lactams, see (f) Metais, E.; Overman, L. E.; Rodriguez, M. I.; Stearns, B. A. J. Org. Chem. 1997, 62, 9210.
98. (a) Blechert, S. Synthesis 1989, 71.
99. (b) Heimgartner, H.; Hansen, H.-J.; Schmid, H. In Iminium Salts in Organic Chemistry, Part 2; Böhme, H., Viche, J. J., Eds.; Wiley: New York, 1979; p 655-732.
100. (c) Winterfeldt, E. Curr. Topics Org. Chem. 1971, 16, 1971.
101. See, for example, (a) Overman, L. E.; Kakimoto, M. A. J. Am. Chem Soc. 1979, 101, 1310.
102. (b) Overman, L. E.; Jacobsen, E. J.; Doedens, R. J. J. Org. Chem. 1983, 48, 3393.
103. (c) Hart, D. J.; Yang, T. K. J. Org. Chem. 1985, 50, 235.
104. (d) Ent, H.; de Koning, H.; Speckamp, W. N. J. Org. Chem. 1986, 51, 1687.
105. For selected references, see (a) Dobbs, A. P.; Guesné, S. J. J.; Hursthouse, M. B.; Coles, S. J. Synlett 2003, 1740.
106. (b) Sun, P.; Sun, C.; Weinreb, S. N. J. Org. Chem. 2002, 67, 4337.
107. (c) Wölfling, J.; Frank, E.; Schneider, G.; Bes, M. T.; Tietze, L. F. Synlett 1998, 1205.
108. (d) Kercher, T.; Livinghouse, T. J. Am. Chem. Soc. 1996, 118, 4200.
109. (e) Gelas-Mialhe, Y.; Gramain, J.-C.; Hajouji, H.; Remuson, R. Heterocycles 1992, 34, 37.
110. (f) Tietze, L. F.; Wünsch, J. R. Angew. Chem., Int. Ed. Engl. 1991, 30, 1697.
111. (g) Overman, L. E.; Sharp, M. J. Tetrahedron Lett. 1988, 29, 901.
112. (h) Kano, S.; Yokomatsu, T.; Yuasav, Y.; Shibuya, S. Heterocycles 1986, 24, 621.
113. (i) Shono, T.; Matsumura, Y.; Uchida, K., Kobayashi, H. J. Org. Chem. 1985, 50, 3243.
114. (j) Hiemstra, H.; Fortgens, H. P.; Speckamp, W. N. Tetrahedron Lett. 1985, 26, 3155.
115. (k) For reviews see Fleming, I.; Barbero, A.; Walter, D. Chem. Rev. 1997, 97, 2063. Langkopf, E.; Schinzer, D. Chem. Rev. 1995, 95, 1375.
116. (k) For reviews see Fleming, I.; Barbero, A.; Walter, D. Chem. Rev. 1997, 97, 2063. Langkopf, E.; Schinzer, D. Chem. Rev. 1995, 95, 1375.
117. For early examples, see: (a) Overman, L. E.; Mendelson, L. T. J. Am. Chem. Soc. 1981, 103, 5579. See also ref 32c,e.
118. Snider, B. B. In Comprehensive Organic Chemistry; Trost, B. M., Fleming, I., Heathcock, C. H., Eds.; Pergamon: New York, 1991; Z, p 523.
119. For recent examples of halooxacycles via Prins cyclizations, see (a) Hart, D. J.; Bennet, C. E. Org. Lett. 2003, 5, 1499.
120. (b) Jaber, J. J.; Mitsui, K.; Rychnovsky, S. D. J. Org. Chem. 2001, 66, 4679.
121. (c) Al-Mutairi, E. H.; Crosby, S. R.; Darzi, J.; Harding, J. R.; Hughes, R. A.; King, C. D.; Simpson, T. J.; Smith, R. W.; Wills, C. L. J. Chem. Soc., Chem. Commun. 2001, 835.
122. (d) Cloninger, M. J.; Overman, L. E. J. Am. Chem. Soc. 1999, 121, 1092.
123. (e) Yang, X.-F.; Li, C. J. Tetrahedron Lett. 2000, 41, 1321.
124. (f) Markó, I. E.; Chellé, F. Tetrahedron Lett. 1997, 38, 2895.
125. (g) Perron-Sierra, F.; Promo, M. A.; Martin, V. A.; Albizati, K. F. J. Org. Chem. 1991, 56, 6188.
126. (h) Coppi, L.; Ricci, A., Taddei, M. J. Org. Chem. 1988, 53, 911.
127. (i) Winstead, R. C.; Simpson, T. H.; Lock, G. A.; Schiawelli, M. D.; Thompson, D. M. J. Org. Chem. 1986, 51, 257 and references therein.
128. Lolkema, L. D. M.; Hiemstra, H.; Semeyn, C.; Speckamp, W. N. Tetrahedron 1994, 50, 7115.
129. Blumenkopf, T. A.; Overman, L. E. Chem. Rev. 1986, 86, 857.
130. Jaber, J. J.; Mitsui, K.; Rychnovsky, S. D. J. Org. Chem. 2001, 66, 4679.
131. For related examples, see Wölfling, J.; Frank, E.; Schneider, G.; Bes, M. T.; Tietze, L. Synlett 1998, 1205. See also refs 34d, 34f, 37i.
132. Deslongchamps, P. Stereoelectronic Effects in Organic Chemistry; Pergamon: New York, 1983; Chapter 6.
133. For relevant reviews, see, for example, (a) Jeffs, P. W. Sceletium alkaloids. In The Alkaloids; Rodrigo, R. G. G., Ed.; Academic: New York, 1981V. 19, p 1.
134. (b) Martin, S. F. Amaryllidaceae alkaloids. In The Alkaloids; Brossi, A., Ed.; Academic: New York, 1987; Vol. 30, p 251.
135. (c) Hoshino, O. In The Alkaloids; Cordell, G. A., Ed.; Academic: New York, 1987; Vol. 51, p 323.
136. (e) Pilli, R. A.; Ferreira de Oliveira, M. C. Stemona alkaloids. Nat. Prod. Rep. 2000, 17, 117.
137. See, for example, (a) Xu, R.; Dwoskin, L. P.; Grinevich, V. P.; Deaciuc, G.; Crooks, P. A. Nicotine analogues. Bioorg. Med. Chem. Lett. 2001, 11, 1245.
138. (b) Hanessian, S.; Papeo, G.; Angiolini, M.; Fettis, K.; Berretta, M.; Munro, A. Constrained proline analogues. J. Org. Chem. 2003, 68, 7204.
139. (c) Portevin, B.; Longchampt, M.; Canet, E.; De Nanteuil, G. Human elastase inhibitors. J. Med. Chem. 1997, 40, 1906.
140. (d) Blankley, C. J.; Kaltenbronn, J. S.; DeJohn, D. E.; Werner, A.; Bennett, L. R.; Bobowski, G.; Krolls, U.; Johnson, D. R.; Pearlman, W. R., Hoefle, M. L.; Essenburg, A. D.; Cohen, D. M.; Kaplan, H. R. ACE inhibitors. J. Med. Chem. 1987, 30, 992.