Stereoselective synthesis of C17–C34 fragment of antascomicin A

This Letter describes the synthesis of C17–C34 unit of antascomicin A. A diastereoselective radical cyclization strategy has been developed to construct the highly substituted cyclohexane ring with required stereochemistry present in the molecule. Other key features in the synthesis are Sharpless asymmetric epoxidation, substrate controlled regioselective epoxide opening reaction with Gilman’s reagent, dithiane mediated CC bond formation reaction, and modified Julia olefination reaction.