Au(I)‐Catalyzed Synthesis of [3,2‐b]pyrrole‐fused Pentacyclic Triterpenoids

Abstract

Gold(I) chloride complex with triphenylphosphine and metal triflates catalyze the formation of novel [3,2‐b]pyrrole‐fused pentacyclic triterpenoids from accessible 2‐alkynyl derivatives of betulonic, ursonic and oleanonic acids. The reactions proceed in the presence of 5 mol% of the catalyst and provide pyrrole‐containing triterpenoids with the isolated yield of 60–86 %.