Syntheses and Absolute Configurations of the Marine Sponge Purines (+)-Agelasimine-A and (+)-Agelasimine-B.

Abstract The first total syntheses of (+)-agelasimine-A and (+)-agelasimine-B, adenine-related bicyclic diterpenoids isolated from the marine sponge Agelas mauritiana, have been achieved via a highly stereoselective route. On the basis of the present results, the absolute configurations of both alkaloids have been defined as shown in stereoformulas (+)-1a and (+)-1b, respectively.