Synthesis of the central C18-C30 core of the phorboxazole natural products

Tetrahedron Letters

Volumn 37, Issue 36, 1996, Pages 6449-6452

  Lee, Chi Sing ^a   Forsyth, Craig J ^a  

^a University of Minnesota ^*  (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CYTOTOXIC AGENT; PHORBOXAZOLE A; PHORBOXAZOLE B; UNCLASSIFIED DRUG;

ARTICLE; CHIRALITY; DRUG SYNTHESIS; REACTION ANALYSIS; STEREOCHEMISTRY;

EID: 0030565511     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4039(96)01435-9     Document Type: Article

References (9)

1. Searle, P. A.; Molinski, T. F. J. Am. Chem. Soc. 1995, 117, 8126-8131.
2. Paterson, I.; Goodman, J. M.; Isaka, M. Tetrahedron Lett. 1989, 30, 7121-7124.
3. Evans, D. A.; Chapman, K. T.; Carreira, E. M. J. Am. Chem. Soc. 1988, 110, 3560-3578.
4. Garner, P.; Park, J. M. J. Org. Chem, 1987, 52, 2361-2364.
5. Blanchette, M. A.; Choy, W.; Davis, J. T.; Essenfeld, A. P.; Masamune, S.; Roush, W. R.; Sakai, T. Tetrahedron Lett. 1984, 25, 2183-2186.
6. Dess, D. B.; Martin, J. C. J. Am. Chem. Soc. 1991, 113, 7277-7287.
7. Because the absolute configuration of the phorboxazoles had not been established, we arbitrarily chose the (S)-enantiomer of 4. This was prepared from methyl (S)-(+)-3-hydroxy-2-methylpropionate and p-methoxybenzyltrichloroacetimidate as described in: Nakajima, N.; Horita, K.; Abe, R.; Yonemitsu, O. Tetrahedron Lett. 1988, 29, 4139-4142.
8. It has been noted that partial racemization occurred with a similar substrate in this type of reaction sequence: Paterson, I.; Lister, M. A. Tetrahedron Lett. 1988, 29, 585-588. This may be reflected here in the moderate yield of the desired diastereomer 6 obtained from subsequent aldol coupling.
9. Aicher, T. D.; Kishi, Y. Tetrahedron Lett. 1987, 28, 3463-3466.