Stereoselective synthesis of 12,13-cyclopropyl-epothilone B and side-chain-modified variants

A general strategy has been devised for the stereoselective synthesis of 12,13-cyclopropyl-epothilone B and side-chain-modified variants thereof, which relies on late stage introduction of the heterocycle through Wittig olefination of ketone 14. Formation of the macrocycle was achieved through RCM-based ring closure and introduction of the cyclopropane moiety involved a highly selective Charette cyclopropanation of allylic alcohol 7.

Total synthesis of hypermodified epothilone analogs with potent in vitro antitumor activity

The convergent total synthesis of hypermodified epothilone analogs 1 and 2 has been achieved with the stereoselective cyclopropanation of allylic alcohol 17 and ring-closing olefin metathesis with diene 22 as the key steps. In spite of significant structural differences between these analogs and the natural epothilone scaffold, 1 and 2 are potent inducers of tubulin polymerization and inhibit the growth of human cancer cells in vitro with sub-nM IC50 values.