First enantioselective total synthesis of (natural) (+)-11,12-epoxy-11,12-dihydrocembrene-C and (-)-7,8-epoxy-7,8-dihydrocembrene-C

The first enantioselective total syntheses of (+)-11,12-epoxy-11,12-dihydro cembrene-C 1 and (-)-7,8-epoxy-7,8-dihydrocembrene-C 2, two naturally occur ring cembranoxides isolated from tropical marine soft corals, are achieved via a general approach by employing an intramolecular McMurry coupling and Sharpless asymmetric epoxidation as key steps from readily available starti ng materials. The syntheses presented here verify the absolute stereochemis try assignment of 1 as (11S,12S) by Bowden et al. two decades ago, and the epoxy configuration of 2 was assumed as (7R,8R) accordingly.