Highly Enantioselective, Organocatalytic and Scalable Synthesis of a rare cis-cis-Tricyclic Diterpenoid

A highly enantioselective, organocatalytic and scalable synthesis of a very unusual cis-decalin-cis-hydrindane tricyclic diterpenoid system has been achieved. Despite the prevalent pharmacological space that the related trans-trans and trans-cis-systems occupy, there have been no reports of an asymmetric synthesis of the cis-cis systems in the literature until now. We demonstrate the flexibility of our approach not only through access to a diverse range of products, all of which are attained in exceptionally high selectivities, but also by showing their easy conversion to the corresponding trans-cis-system and other derivatives.