Synthesis of dolastatin 15

Abstract

The present invention relates to the synthesis of natural (-)- dolastatin and the elucidation of the absolute configuration of this important sea hare constituent. A segment synthetic strategy was utilized for obtaining the Dolabella auricularia (Indian Ocean sea hare) depsipeptide dolastatin 15. Reaction of protected (S)-Hiva-(S)-Phe (2c) with isopropenyl chloroformate followed by Meldrum's ester, cyclization (2c.fwdarw.3a) of the product in toluene and finally methylation afforded the key (S)-dolapyrrolidine (Dpy) derivative (3b). Condensation of tripeptide (8) with the three unit Dpy segment (5b) followed by deprotection and coupling (diethyl phosphorocyanidate) led to dolastatin 15 in 11% overall yield. The powerful and selective activity of dolastatin 15 against the U.S. National Cancer Institute's panel of human cell lines is reported.

Dependencies are inferred from the claim text.