Stereoselective Synthesis of C1-C6 and C7-C22 Fragments of (-) Callystatin A

The stereoselective synthesis of the two major fragments (C1-C6 and C7-C22) of cytotoxic polyketide marine natural product (-) callystatin A, has been achieved with Sharpless epoxidation, desymmetrization strategy, Horner-Wadsworth-Emmons reaction and witting olefination