Chemical Synthesis of Brasilicardins

Brasilicardins A-D, isolated from the culture broth of the actinomycete Nocardia brasiliensis IFM 0406, constitute a class of natural products with a unique structure consisting of a highly strained tricyclic terpenoid core with the central ring in the boat conformation, an amino acid, and a mono- or disaccharide. These molecules display potent immunosuppressive activities and their intriguing biological and structural aspects make brasilicardins attractive synthetic targets. In 2018, we achieved the total synthesis of all brasilicardins A-D. In this account, our efforts toward the completion of a unified total synthesis of brasilicardins are described, focusing on the development of methodologies directed towards construction of the characteristic tricyclic terpenoid core, which represents the most critical and challenging task of the chemical synthesis.