Total syntheses of yingzhaosu A and of its C(14)-epimer including the first evaluation of their antimalarial and cytotoxic activities

Journal of Organic Chemistry

Volumn 70, Issue 9, 2005, Pages 3618-3632

  Szpilman, Alex M ^a   Korshin, Edward E ^a   Rozenberg, Haim ^a   Bachi, Mario D ^a  

^a WEIZMANN INSTITUTE OF SCIENCE   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

ALCOHOLS; ALDEHYDES; CATALYST ACTIVITY; CHEMICAL BONDS; DEHYDRATION; HYDROGENATION; ISOMERS; MALARIA CONTROL; MOLECULAR STRUCTURE; TOXIC MATERIALS;

ANTIMALARIAL AGENT; MOLECULAR CORE; NUCLEOPHILIC REAGENTS; STEREOGENIC CENTERS;

SYNTHESIS (CHEMICAL);

4,8 DIMETHYL 2,3 DIOXABICYCLO[3.3.1]NONANE 4 CARBALDEHYDE; ALDEHYDE DERIVATIVE; ALLYL COMPOUND; ENDOPEROXIDE; FREE RADICAL; FUSED HETEROCYCLIC RINGS; PEROXIDE; REDUCING AGENT; UNCLASSIFIED DRUG; YINGZHAOSU A;

ACETALIZATION; ANTIMALARIAL ACTIVITY; ARTICLE; CANCER CELL; CATALYST; CELL STRAIN KB; CHEMICAL BOND; CHEMICAL REACTION; CHEMICAL STRUCTURE; CYTOTOXICITY; DEHYDRATION; DRUG SYNTHESIS; EPIMER; HYDROGENATION; MUKAIYAMA REACTION; NASOPHARYNX CANCER; QUANTITATIVE ANALYSIS; SENSITIVITY ANALYSIS; STRUCTURE ACTIVITY RELATION;

ANTIMALARIALS; ANTINEOPLASTIC AGENTS, PHYTOGENIC; CATALYSIS; HUMANS; MOLECULAR STRUCTURE; PEROXIDES; SESQUITERPENES; STEREOISOMERISM; STRUCTURE-ACTIVITY RELATIONSHIP; TUMOR CELLS, CULTURED;

EID: 17744377209     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo050074z     Document Type: Article

References (89)

1. Liang, X. T.; Yu, D. Q.; Wu, W. L.; Deng, H. C. Acta Chim. Sin. 1979, 37, 215-230.
2. (a) Xu, X. X.; Zhu, J.; Huang, D.-Z.; Zhou, W.-S. Tetrahedron Lett. 1991, 32, 5785-5788.
3. (b) Zhou, W. S.; Xu, X. X. Acc. Chem. Res. 1994, 27, 211-216.
4. Qualitative statements concerning the antimalarial activity of yingzhaosu A (1) are given in ref 2 and in: (a) Liang, X. T. In Advances in Chinese Medicinal Materials; Chang, H. M., Yeung, H. W., Tso, W. W., Koo, A., Eds.; World Scientific Publ: Singapore, 1985; pp 427-432. (b) Tang, W.; Eisenbrand, G. Chinese Drugs of Plant Origin. Chemistry, Pharmacology and Use in Traditional and Modern Medicine; Springer-Verlag: Berlin, 1992; pp 165-166.
5. Qualitative statements concerning the antimalarial activity of yingzhaosu A (1) are given in ref 2 and in: (a) Liang, X. T. In Advances in Chinese Medicinal Materials; Chang, H. M., Yeung, H. W., Tso, W. W., Koo, A., Eds.; World Scientific Publ: Singapore, 1985; pp 427-432. (b) Tang, W.; Eisenbrand, G. Chinese Drugs of Plant Origin. Chemistry, Pharmacology and Use in Traditional and Modern Medicine; Springer-Verlag: Berlin, 1992; pp 165-166.
6. Zhang, L.; Zhou, W.-S.; Xu, X. X. J. Chem. Soc., Chem. Commun. 1988, 523-524.
7. (a) Jefford, C. W. In Advances in Drug Research. Vol.29: Peroxidic Antimalarials; Jefford, C. W., Ed.; Academic Press: 1997; pp 270-325.
8. (b) Jefford, C. W. Curr. Med. Chem. 2001, 8, 1803-1826.
9. Lin, M.-Y.; Ni, J.-M.; Fan, J. F.; Tu, Y.-Y.; Wu, Z.-H.; Wu Y.-L.; Chou, W.-S. Acta Chim. Sin. 1979, 37, 129-141.
10. For some recent reviews, see: (a) Posner, G. H.; O'Neill, P. M. Acc. Chem. Res. 2004, 37, 397-404. (b) O'Neill, P. M.; Posner, G. H. J. Med. Chem. 2004, 47, 2945-2964. (c) Tang, Y.; Dong, Y.; Vennerstrom J. L. Med. Res. Rev. 2004, 24, 425-448. (d) Jung, M.; Lee, K.; Kim, H.; Park, M. Curr. Med. Chem. 2004, 11, 1265-1284. (e) Bez, G.; Kalita, B.; Sarmah, P.; Barua, N. C.; Dutta, D. K. Curr. Org. Chem. 2003, 7, 1231-1255. (f) Robert, A.; Dechy-Cabaret, O.; Cazelles, J.; Meunier, B. Acc. Chem. Res. 2002, 35, 167-174. (g) Vroman, J. A.; Alvim-Gaston, M.; Avery, M. A. Curr. Pharm. Des. 1999, 5, 101-138. (h) Bhattacharya, A. K.; Sharma, R. P. Heterocycles 1999, 51, 1681-1745. See also ref 5.
11. For some recent reviews, see: (a) Posner, G. H.; O'Neill, P. M. Acc. Chem. Res. 2004, 37, 397-404. (b) O'Neill, P. M.; Posner, G. H. J. Med. Chem. 2004, 47, 2945-2964. (c) Tang, Y.; Dong, Y.; Vennerstrom J. L. Med. Res. Rev. 2004, 24, 425-448. (d) Jung, M.; Lee, K.; Kim, H.; Park, M. Curr. Med. Chem. 2004, 11, 1265-1284. (e) Bez, G.; Kalita, B.; Sarmah, P.; Barua, N. C.; Dutta, D. K. Curr. Org. Chem. 2003, 7, 1231-1255. (f) Robert, A.; Dechy-Cabaret, O.; Cazelles, J.; Meunier, B. Acc. Chem. Res. 2002, 35, 167-174. (g) Vroman, J. A.; Alvim-Gaston, M.; Avery, M. A. Curr. Pharm. Des. 1999, 5, 101-138. (h) Bhattacharya, A. K.; Sharma, R. P. Heterocycles 1999, 51, 1681-1745. See also ref 5.
12. For some recent reviews, see: (a) Posner, G. H.; O'Neill, P. M. Acc. Chem. Res. 2004, 37, 397-404. (b) O'Neill, P. M.; Posner, G. H. J. Med. Chem. 2004, 47, 2945-2964. (c) Tang, Y.; Dong, Y.; Vennerstrom J. L. Med. Res. Rev. 2004, 24, 425-448. (d) Jung, M.; Lee, K.; Kim, H.; Park, M. Curr. Med. Chem. 2004, 11, 1265-1284. (e) Bez, G.; Kalita, B.; Sarmah, P.; Barua, N. C.; Dutta, D. K. Curr. Org. Chem. 2003, 7, 1231-1255. (f) Robert, A.; Dechy-Cabaret, O.; Cazelles, J.; Meunier, B. Acc. Chem. Res. 2002, 35, 167-174. (g) Vroman, J. A.; Alvim-Gaston, M.; Avery, M. A. Curr. Pharm. Des. 1999, 5, 101-138. (h) Bhattacharya, A. K.; Sharma, R. P. Heterocycles 1999, 51, 1681-1745. See also ref 5.
13. For some recent reviews, see: (a) Posner, G. H.; O'Neill, P. M. Acc. Chem. Res. 2004, 37, 397-404. (b) O'Neill, P. M.; Posner, G. H. J. Med. Chem. 2004, 47, 2945-2964. (c) Tang, Y.; Dong, Y.; Vennerstrom J. L. Med. Res. Rev. 2004, 24, 425-448. (d) Jung, M.; Lee, K.; Kim, H.; Park, M. Curr. Med. Chem. 2004, 11, 1265-1284. (e) Bez, G.; Kalita, B.; Sarmah, P.; Barua, N. C.; Dutta, D. K. Curr. Org. Chem. 2003, 7, 1231-1255. (f) Robert, A.; Dechy-Cabaret, O.; Cazelles, J.; Meunier, B. Acc. Chem. Res. 2002, 35, 167-174. (g) Vroman, J. A.; Alvim-Gaston, M.; Avery, M. A. Curr. Pharm. Des. 1999, 5, 101-138. (h) Bhattacharya, A. K.; Sharma, R. P. Heterocycles 1999, 51, 1681-1745. See also ref 5.
14. For some recent reviews, see: (a) Posner, G. H.; O'Neill, P. M. Acc. Chem. Res. 2004, 37, 397-404. (b) O'Neill, P. M.; Posner, G. H. J. Med. Chem. 2004, 47, 2945-2964. (c) Tang, Y.; Dong, Y.; Vennerstrom J. L. Med. Res. Rev. 2004, 24, 425-448. (d) Jung, M.; Lee, K.; Kim, H.; Park, M. Curr. Med. Chem. 2004, 11, 1265-1284. (e) Bez, G.; Kalita, B.; Sarmah, P.; Barua, N. C.; Dutta, D. K. Curr. Org. Chem. 2003, 7, 1231-1255. (f) Robert, A.; Dechy-Cabaret, O.; Cazelles, J.; Meunier, B. Acc. Chem. Res. 2002, 35, 167-174. (g) Vroman, J. A.; Alvim-Gaston, M.; Avery, M. A. Curr. Pharm. Des. 1999, 5, 101-138. (h) Bhattacharya, A. K.; Sharma, R. P. Heterocycles 1999, 51, 1681-1745. See also ref 5.
15. For some recent reviews, see: (a) Posner, G. H.; O'Neill, P. M. Acc. Chem. Res. 2004, 37, 397-404. (b) O'Neill, P. M.; Posner, G. H. J. Med. Chem. 2004, 47, 2945-2964. (c) Tang, Y.; Dong, Y.; Vennerstrom J. L. Med. Res. Rev. 2004, 24, 425-448. (d) Jung, M.; Lee, K.; Kim, H.; Park, M. Curr. Med. Chem. 2004, 11, 1265-1284. (e) Bez, G.; Kalita, B.; Sarmah, P.; Barua, N. C.; Dutta, D. K. Curr. Org. Chem. 2003, 7, 1231-1255. (f) Robert, A.; Dechy-Cabaret, O.; Cazelles, J.; Meunier, B. Acc. Chem. Res. 2002, 35, 167-174. (g) Vroman, J. A.; Alvim-Gaston, M.; Avery, M. A. Curr. Pharm. Des. 1999, 5, 101-138. (h) Bhattacharya, A. K.; Sharma, R. P. Heterocycles 1999, 51, 1681-1745. See also ref 5.
16. For some recent reviews, see: (a) Posner, G. H.; O'Neill, P. M. Acc. Chem. Res. 2004, 37, 397-404. (b) O'Neill, P. M.; Posner, G. H. J. Med. Chem. 2004, 47, 2945-2964. (c) Tang, Y.; Dong, Y.; Vennerstrom J. L. Med. Res. Rev. 2004, 24, 425-448. (d) Jung, M.; Lee, K.; Kim, H.; Park, M. Curr. Med. Chem. 2004, 11, 1265-1284. (e) Bez, G.; Kalita, B.; Sarmah, P.; Barua, N. C.; Dutta, D. K. Curr. Org. Chem. 2003, 7, 1231-1255. (f) Robert, A.; Dechy-Cabaret, O.; Cazelles, J.; Meunier, B. Acc. Chem. Res. 2002, 35, 167-174. (g) Vroman, J. A.; Alvim-Gaston, M.; Avery, M. A. Curr. Pharm. Des. 1999, 5, 101-138. (h) Bhattacharya, A. K.; Sharma, R. P. Heterocycles 1999, 51, 1681-1745. See also ref 5.
17. For some recent reviews, see: (a) Posner, G. H.; O'Neill, P. M. Acc. Chem. Res. 2004, 37, 397-404. (b) O'Neill, P. M.; Posner, G. H. J. Med. Chem. 2004, 47, 2945-2964. (c) Tang, Y.; Dong, Y.; Vennerstrom J. L. Med. Res. Rev. 2004, 24, 425-448. (d) Jung, M.; Lee, K.; Kim, H.; Park, M. Curr. Med. Chem. 2004, 11, 1265-1284. (e) Bez, G.; Kalita, B.; Sarmah, P.; Barua, N. C.; Dutta, D. K. Curr. Org. Chem. 2003, 7, 1231-1255. (f) Robert, A.; Dechy-Cabaret, O.; Cazelles, J.; Meunier, B. Acc. Chem. Res. 2002, 35, 167-174. (g) Vroman, J. A.; Alvim-Gaston, M.; Avery, M. A. Curr. Pharm. Des. 1999, 5, 101-138. (h) Bhattacharya, A. K.; Sharma, R. P. Heterocycles 1999, 51, 1681-1745. See also ref 5.
18. (a) Hoffheinz, W.; Schmid, G.; Stohler, H. Eur. Pat. Appl. 311955, 1989; Chem. Abstr. 1990, 112, 20999.
19. (b) Hofheinz, W.; Burgin, H.; Gocke, E.; Jaquet, C.; Masciadri, R.; Schmid, G.; Stohler, H.; Urwyler, H. Trop. Med. Parasitol. 1994, 45, 261-265.
20. (c) Jaquet, C.; Stohler, H. R.; Chollet, J.; Peters, W. Trop. Med. Parasitol. 1994, 45, 266-271.
21. (a) Bachi, M. D.; Korshin, E. E.; Hoos, R.; Szpilman, A. M.; Cumming, J. N.; Plyopradith, P.; Xie, S. J.; Shapiro, T. A.; Posner, G. H. J. Med. Chem. 2003, 46, 2516-2533.
22. (b) Bachi, M. D.; Korshin, E. E.; Ploypradith, P.; Cumming, J. N.; Xie, S. J.; Shapiro, T. A.; Posner, G. H. Bioorg. Med. Chem. Lett. 1998, 8, 903-908.
23. (c) Bachi, M. D.; Posner, G. H.; Korshin, E. E. PCT Int. Appl. WO 99/12900, 1999; Chem. Abstr. 1999, 130, 237573.
24. (a) Korshin, E. E.; Hoos, R.; Szpilman, A. M.; Konstantinovski, L.; Posner, G. H.; Bachi, M. D. Tetrahedron 2002, 58, 2449-2469.
25. (b) Bachi, M. D.; Korshin, E. E. Synlett 1998, 122-124.
26. O'Neill, P. M.; Stocks, P. A.; Pugh, M. D.; Araujo, N. C.; Korshin, E. E.; Bickley, J. F.; Ward, S. A.; Bray, P. G.; Pasini, E.; Davies, J.; Verissimo, E.; Bachi, M. D. Angew. Chem., Int. Ed. 2004, 43, 4193-4197.
27. O'Neill, P. M.; Searle, N. L.; Raynes, K. J.; Maggs, J. L.; Ward, S. A.; Storr, R. C.; Park, B. K.; Posner, G. H. Tetrahedron Lett. 1998, 39, 6065-6068.
28. (a) Kim, H.-S.; Begum, K.; Ogura, N.; Wataya, Y.; Tokuyasu, T.; Masuyama, A.; Nojima, M.; McCullough, K. J. J. Med. Chem. 2002, 45, 4732-4736.
29. (b) Tokuyasu, T.; Masuyama, A.; Nojima, M.; McCullough, K. J.; Kim, H.-S.; Wataya, Y. Tetrahedron 2001, 57, 5979-5989.
30. (c) Tokuyasu, T.; Masuyama, A.; Nojima, M.; Kim, H.-S.; Wataya, Y. Tetrahedron Lett. 2000, 41, 3145-3148.
31. Boukouvalas, J.; Haynes, R. K. In Radicals in Organic Synthesis. Vol.2: Applications; Renaud, P.; Sibi, M. P., Eds.; Wiley-VCH: Weinheim, 2001; pp 455-484.
32. A preliminary brief report on our first-version total synthesis of yingzhaosu A (1) was included in the proceedings to 17th International Congress of Heterocyclic Chemistry, Vienna, Austria, Aug 1999: Bachi, M. D.; Korshin, E. E.; Hoos, R.; Szpilman, A. M. J. Heterocycl. Chem. 2000 37, 639-646.
33. For the safety precautions in working with endoperoxides, see ref 10a.
34. For reviews on the Pummerer reaction, see: (a) De Lucchi, O.; Miotti, U.; Modena, G. Org. React. 1991, 40, 157-405. (b) Moiseenkov, A. M.; Dragan, V. A.; Veselovski, V. V. Russ. Chem. Rev. 1991, 60, 643-657.
35. For reviews on the Pummerer reaction, see: (a) De Lucchi, O.; Miotti, U.; Modena, G. Org. React. 1991, 40, 157-405. (b) Moiseenkov, A. M.; Dragan, V. A.; Veselovski, V. V. Russ. Chem. Rev. 1991, 60, 643-657.
36. (a) Kornblum, N.; DeLamare, H. E. J. Am. Chem. Soc. 1951, 73, 880-881.
37. (b) Clennan, E. L.; Foote, C. S. In Organic Peroxides; Ando, W., Ed.; Wiley: Chichester, 1992; pp 255-318.
38. (c) Saito, I.; Nittala, S. S. In The Chemistry of Peroxides; Patai, S., Ed.; Wiley: Chichester, 1983; pp 311-374.
39. Szpilman, A. M.; Korshin, E. E.; Hoos, R.; Posner, G. H.; Bachi, M. D. J. Org. Chem. 2001, 66, 6531-6540.
40. Attempts to convert the tertiary hydroxyl at C(8) into various thionocarbonates, thionocarbamates or oxalyl thiohydroxamates for further application of the Barton-McCombie free radical deoxygenation failed.
41. See the Experimental Section.
42. Satchell, D. N. P.; Satchell, R. S. Chem. Soc. Rev. 1990, 19, 55-81.
43. Muxfeldt, H.; Unterweger, W.-D.; Helmchen, G. Synthesis 1976, 694-696.
44. (a) Corey, E. J.; Hase, T. Tetrahedron Lett. 1975, 3267-3268.
45. (b) Degani, I.; Foci, R.; Regondi, V. Synthesis 1981, 51-53.
46. (c) Soderquist, J. A.; Miranda, J. L. J. Am. Chem. Soc. 1992, 114, 10078.
47. (d) Cazes, B.; Julia, S. Tetrahedron Lett. 1978, 4065-4068.
48. Craig, D.; Daniels, K.; Mackenzie, A. R. Tetrahedron Lett. 1990, 31, 6441-6444.
49. Patwardhan, S. A.; Dev, S. Synthesis 1974, 348-349.
50. (a) Baudin, J. B.; Hareau, G.; Julia, S. A.; Lorne, R.; Ruel, O. Bull. Soc. Chim. Fr. 1993, 130, 856-878.
51. (b) Baudin, J. B.; Hareau, G.; Julia, S. A.; Ruel, O. Bull. Soc. Chim. Fr. 1993, 130, 336-357.
52. (c) Blakemore, P. R.; Cole, W. J.; Kocienski, P. J.; Morley, A. Synlett 1998, 26-28.
53. For leading general reviews on the Wittig and the related Horner-Wadsworth-Emmons phosphorus-based olefinations, see: (a) Maryanoff, B. E.; Reitz, A. B. Chem. Rev. 1989, 89, 863-927. (b) Clayden, J.; Warren, S. Angew. Chem., Int. Ed. Engl. 1996, 35, 241-270. (c) Vedejs, E.; Peterson, M. J. Adv. Carbanion Chem. 1996, 2, 1-85. (d) Rein, T.; Pedersen, T. Synthesis 2002, 579-594. (e) Molt, O.; Schrader, T. Synthesis 2002, 2633-2670. (f) Valentine, D. H., Jr.; Hillhouse, J. H. Synthesis 2003, 317-334.
54. For leading general reviews on the Wittig and the related Horner-Wadsworth-Emmons phosphorus-based olefinations, see: (a) Maryanoff, B. E.; Reitz, A. B. Chem. Rev. 1989, 89, 863-927. (b) Clayden, J.; Warren, S. Angew. Chem., Int. Ed. Engl. 1996, 35, 241-270. (c) Vedejs, E.; Peterson, M. J. Adv. Carbanion Chem. 1996, 2, 1-85. (d) Rein, T.; Pedersen, T. Synthesis 2002, 579-594. (e) Molt, O.; Schrader, T. Synthesis 2002, 2633-2670. (f) Valentine, D. H., Jr.; Hillhouse, J. H. Synthesis 2003, 317-334.
55. For leading general reviews on the Wittig and the related Horner-Wadsworth-Emmons phosphorus-based olefinations, see: (a) Maryanoff, B. E.; Reitz, A. B. Chem. Rev. 1989, 89, 863-927. (b) Clayden, J.; Warren, S. Angew. Chem., Int. Ed. Engl. 1996, 35, 241-270. (c) Vedejs, E.; Peterson, M. J. Adv. Carbanion Chem. 1996, 2, 1-85. (d) Rein, T.; Pedersen, T. Synthesis 2002, 579-594. (e) Molt, O.; Schrader, T. Synthesis 2002, 2633-2670. (f) Valentine, D. H., Jr.; Hillhouse, J. H. Synthesis 2003, 317-334.
56. For leading general reviews on the Wittig and the related Horner-Wadsworth-Emmons phosphorus-based olefinations, see: (a) Maryanoff, B. E.; Reitz, A. B. Chem. Rev. 1989, 89, 863-927. (b) Clayden, J.; Warren, S. Angew. Chem., Int. Ed. Engl. 1996, 35, 241-270. (c) Vedejs, E.; Peterson, M. J. Adv. Carbanion Chem. 1996, 2, 1-85. (d) Rein, T.; Pedersen, T. Synthesis 2002, 579-594. (e) Molt, O.; Schrader, T. Synthesis 2002, 2633-2670. (f) Valentine, D. H., Jr.; Hillhouse, J. H. Synthesis 2003, 317-334.
57. For leading general reviews on the Wittig and the related Horner-Wadsworth-Emmons phosphorus-based olefinations, see: (a) Maryanoff, B. E.; Reitz, A. B. Chem. Rev. 1989, 89, 863-927. (b) Clayden, J.; Warren, S. Angew. Chem., Int. Ed. Engl. 1996, 35, 241-270. (c) Vedejs, E.; Peterson, M. J. Adv. Carbanion Chem. 1996, 2, 1-85. (d) Rein, T.; Pedersen, T. Synthesis 2002, 579-594. (e) Molt, O.; Schrader, T. Synthesis 2002, 2633-2670. (f) Valentine, D. H., Jr.; Hillhouse, J. H. Synthesis 2003, 317-334.
58. For leading general reviews on the Wittig and the related Horner-Wadsworth-Emmons phosphorus-based olefinations, see: (a) Maryanoff, B. E.; Reitz, A. B. Chem. Rev. 1989, 89, 863-927. (b) Clayden, J.; Warren, S. Angew. Chem., Int. Ed. Engl. 1996, 35, 241-270. (c) Vedejs, E.; Peterson, M. J. Adv. Carbanion Chem. 1996, 2, 1-85. (d) Rein, T.; Pedersen, T. Synthesis 2002, 579-594. (e) Molt, O.; Schrader, T. Synthesis 2002, 2633-2670. (f) Valentine, D. H., Jr.; Hillhouse, J. H. Synthesis 2003, 317-334.
59. Szpilman, A. M. Ph.D. Thesis, the Weizmann Institute of Science, Rehovot, 2003.
60. 3P=CHCOPh (6 equiv) to give after 30 days at rt the corresponding (1R,4R,5R,8R)-8-acetoxy-4,8-dimethyl-4-(3-oxo-3- phenyl-1-propenyl)-2,3-dioxabicyclo-[3.3.1]nonane (48%) and 5% recovered aldehyde. The experimental details are described in the Supporting Information. For few additional examples of Wittig reactions of structurally related bridged bicyclic endoperoxide aldehydes with semistabilized phosphorus ylides, see refs 8a,b and 11.
61. It has been noted that olefination of less sterically hindered secondary aldehydes, having acyclic peroxide moiety, through the Horner-Emmons reaction with phosphineoxide carbanions is considerably more efficient than using Wittig's phosphorus ylides. See: Dussault, P. Synlett 1995, 997-1003.
62. For reviews on Mukaiyama aldol addition, see: (a) Mukaiyama, T. Org. React. 1982, 28, 203-301. (b) Cowden, C. J.; Paterson, I. Org. React. 1997, 51, 1-200. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Palomo, C.; Oiarbide, M.; Garcia, J. M. Chem. Soc. Rev. 2004, 33, 65-75.
63. For reviews on Mukaiyama aldol addition, see: (a) Mukaiyama, T. Org. React. 1982, 28, 203-301. (b) Cowden, C. J.; Paterson, I. Org. React. 1997, 51, 1-200. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Palomo, C.; Oiarbide, M.; Garcia, J. M. Chem. Soc. Rev. 2004, 33, 65-75.
64. For reviews on Mukaiyama aldol addition, see: (a) Mukaiyama, T. Org. React. 1982, 28, 203-301. (b) Cowden, C. J.; Paterson, I. Org. React. 1997, 51, 1-200. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Palomo, C.; Oiarbide, M.; Garcia, J. M. Chem. Soc. Rev. 2004, 33, 65-75.
65. For reviews on Mukaiyama aldol addition, see: (a) Mukaiyama, T. Org. React. 1982, 28, 203-301. (b) Cowden, C. J.; Paterson, I. Org. React. 1997, 51, 1-200. (c) Mahrwald, R. Chem. Rev. 1999, 99, 1095-1120. (d) Palomo, C.; Oiarbide, M.; Garcia, J. M. Chem. Soc. Rev. 2004, 33, 65-75.
66. Titanium tetrachloride mediated bis-aldol addition of artemether (a 1,2,4-trioxane containing a fused cyclic acetal fragment) to bis-trimethylsilyl enol-ethers has been recently applied for synthesis of highly active antimalarial and antitumor 1,2,4-trioxane dimers. See: Posner, G. H.; Ploypradith, P.; Parker, M. H.; O'Dowd, H.; Woo, S.-H.; Nortrop, J.; Krasavin, M.; Dolan, P.; Kensler, T. W.; Xie, S.; Shapiro, T. A. J. Med. Chem. 1999, 42, 4275-4280.
67. (a) Sakai, T.; Ito, H.; Yamawaki, T.; Takeda, A. Tetrahedron Lett. 1984, 25, 2987-2988.
68. (b) Limat, D.; Schlosser, M. Tetrahedron 1995, 51, 5799-5806.
69. (a) According to a literature search using the SciFinder database, the only report on a one-pot Mukaiyama reaction directed toward synthesis of α,β-unsaturated ketones has been found. The reported procedure consists of the sequential treatment of an initially formed titanium aldol product with TFAA followed by triethylamine See: Bouhlel, E.; Ben Hassine, B. Synth. Commun. 1992, 22, 2183-2186.
70. 2-catalyzed condensation of some silyl enol-ethers with dialkylacetals was reported to produce α, β-unsaturated ketones. See: Makin, S. M.; Kruglikova, R. I.; Tagirov, T. K.; Kharitonova, O. V. Russ. J. Org. Chem. (Engl. Ed.) 1984, 20, 1075-1078.
71. Attempts to employ in the aldol addition the TBS-analogue of TMS-enol ether 35 were unsuccessful.
72. (a) Boschelli, D.; Takemasa, T.; Nishitani, Y.; Masamune, S. Tetrahedron Lett. 1985, 26, 5239-2542.
73. (b) Nelson, T. D.; Crouch, R. D. Synthesis 1996, 1031-1069.
74. (a) Gemal, A. L.; Luche, J.-L. J. Am. Chem. Soc. 1981, 103, 5454-5459.
75. (b) Gemal, A. L.; Luche, J. L. Tetrahedron Lett. 1981, 22, 4077-4080.
76. Wilson, K. E.; Sediner, R. T.; Masamune, S. J. Chem. Soc., Chem. Commun. 1970, 213-214.
77. (a) Noyori, R.; Tomino, I.; Tanimoto, Y.; Nishizawa, M. J. Am. Chem. Soc. 1984, 106, 6709-6716.
78. (b) Noyori, R.; Tomino, I.; Yamada, M.; Nishizawa, M. J. Am. Chem. Soc. 1984, 106, 6717-6725.
79. (a) Corey, E. J.; Bakshi, R. K.; Shibata, S.; Chen, C. P.; Singh, V. K. J. Am. Chem. Soc. 1987, 109, 7925-7926.
80. (b) Corey, E. J.; Bakshi, R. K.; Shibata, S. J. Am. Chem. Soc. 1987, 109, 5551-5553.
81. Similar reversals of stereoselectivity have been reported previously. See: Corey, E. J.; Helal, C. J. Angew. Chem., Int. Ed. 1998, 37, 1987-2012 and references therein.
82. 42 This disadvantage was minimized by recovering from the reaction mixture the expensive amino alcohol (80%), which was used for generating the CBS reagent (42).
83. (a) Kutney, J. P.; Ratcliffe, A. H. Synth. Commun. 1975, 5, 47-52.
84. (b) Armstrong, A. In Encyclopedia of Reagents for Organic Synthesis. Vol. 2; Paquette, L. A. Ed.; Wiley: Chichester, 1995; pp 1006-1010.
85. Brown, H. C.; Narasimhan, S.; Choi, Y. M. J. Org. Chem. 1982, 47, 4702-4708.
86. Crystallographic data for the structure of yingzhaosu A(1) have been deposited with the Cambridge Crystallographic Data Center (CCDC) and allocated the deposition number CCDC 253141. Copies of the data can be obtained, free of charge, on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, U.K. (fax: +44-1223-336033 or e-mail: deposit@ccdc.cam.ca.uk).
87. In vitro antimalarial and cytotoxic activities were determined by Prof. Simon L. Croft, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, U.K.
88. 50 values were obtained by graphic interpolations. The testing was performed by Mr. Brian L. Robinson, CTAC, Northwick Park Institute for Medical Research, Harrow, Middlesex, U.K.
89. Xavier, L. C.; Mohan, J. J.; Mathre, D. J.; Thompson, A. S.; Carroll, J. D.; Corley, E. G.; Desmond, R. Organic Syntheses; Wiley: New York, 1998; Collect. Vol. IX, pp 679-688.