Studies towards Bioinspired Synthesis of Hetidine-Type C20-Diterpenoid Alkaloids

Abstract

Details of a biogenetically inspired strategy that led to the synthesis of the hetidine-type C20-diterpenoid alkaloid skeleton are reported in this paper. Key steps of our synthesis include a C—H oxidation to convert the atisine-type core to the ajaconine skeleton, as well as an aza-Prins cyclization that establishes the hetidine alkaloid skeleton. An unexpected heptacyclic framework bearing a unique tricyclo[3.3.1.02,7]nonane moiety has been obtained during our studies, which may represent a new type of C20-diterpenoid alkaloids yet to be discovered.