Asymmetric total synthesis of (+)-ovafolinins A and B.

(+)-Ovafolinins A and B are two homologous lignans containing unique polycyclic skeletons. Benefiting from a highly diastereoselective alkylation of (S)-Taniguchi lactone, a double Friedel-Crafts reaction, a global debenzylation and a Cu(OAc)2-enabled benzylic oxidative cyclization, we present herein an efficient synthetic approach to (+)-ovafolinins A and B.