Asymmetric total synthesis of (-)-plicatic acid via a highly enantioselective and diastereoselective nucleophilic epoxidation of acyclic trisubstitued olefins.

The first total synthesis of (-)-plicatic acid has been achieved by a concise and enantioselective route. In this synthesis, a conceptually new strategy featuring an asymmetric epoxidation-intramolecular epoxy-ring-opening Friedel-Crafts reaction sequence was developed for the stereoselective construction of the 2,7'-cyclolignane skeleton bearing contiguous quaternary-quaternary-tertiary stereocenters. The implementation of this strategy was enabled by the development of a modified protocol for the Seebach epoxidation with TADOOH, which affords an unprecedented, highly enantioselective and diastereoselective epoxidation with a range of alpha-carbonyl-beta-substituted acrylates 3.