Complestatin to chloropeptin I via a quantitative acid catalyzed rearrangement. Absolute stereochemical determination of complestatin.

Complestatin and isomeric chloropeptin I are bicyclo hexapeptides isolated from a Streptomyces sp. Both of these compounds are inhibitors of gp120-CD4 HIV fusion activity. In this paper, we describe an efficient acid catalyzed conversion of complestatin to chloropeptin I, provide a plausible mechanism for this transformation, and unambiguously assign the stereochemistry of complestatin.