Synthesis of γ-lactones by desymmetrization. A synthesis of (−)-muricatacin

A short synthesis of the natural potent cytotoxic agent (−)-muricatacin 1 and related unsaturated lactones from a versatile common intermediate, dienedioate 2, derived from d-mannitol or tartaric acid, is described. The strategy depends upon the desymmetrization of 7 by dihydroxylation and elaboration of the hydroxy alkyl sidechain. A route to unsaturated lactones is also described using a cis selective Wittig reaction. Since the enantiomers of 2 are available from the corresponding tartaric acids, this method provides access to both enantiomers of the described compounds and a wide range of derivatives.