Total synthesis of (+)-allocyathin B₂, (-)-erinacine B, and (-)-erinacine E

This article describes the enantioselective total synthesis of (+)-allocyathin B₂ and (-)-erinacine B via the convergent approach using new chiral building blocks prepared by the asymmetric catalysis developed in our research, and also describes the biomimetic total synthesis of (-)-erinacine E. The convergent approach developed in these studies would enable the divergent synthesis of optically pure cyathane diterpenoids and their derivatives for SAR.