Synthetic studies towards volvalerenol A: access to a fully functionalized cycloheptane framework in an asymmetric fashion through the exploitation of C 2 -symmetry.

The enantioselective synthesis of a fully functionalized cycloheptane core of the naturally occurring triterpenoid volvalerenol A, exhibiting pseudo- C 2 symmetry, was achieved. Enantioselective enzymatic desymmetrization (EED), asymmetric methallylation, and reductive ring opening of an cyclopropane overbred intermediate were the key reactions to access the cycloheptanone core. Further synthetic manipulations, via a unique "MPV" (Meerwein-Ponndorf-Verley) type reductive ring-opening of an epoxide and other synthetic transformations, afforded two fully functionalized cycloheptane frameworks of the target molecule.