Towards the Total Synthesis of Schisandrene: Stereoselective Synthesis of the Dibenzocyclooctadiene Lignan Core

Abstract

A stereoselective synthesis of the dibenzocyclooctadiene lignan core of the natural product schisandrene is described. Starting from readily available gallic acid, the synthetic strategy involves Suzuki-Miyaura cross-coupling, Stille reaction, and ring-closing metathesis (RCM) in the reaction sequence. The required asymmetric center at C-7' was established by an asymmetric reduction of a keto compound using the Corey-Bakshi-Shibata (CBS) catalyst. In our approach, the eight-membered ring was achieved by RCM for the first time.