Gold‐Catalyzed Oxidative Cyclization of Tryptamine Derived Enynamides: A Stereoselective Approach to Tetracyclic Spiroindolines

In this work, we describe a new gold‐catalyzed oxidative cascade cyclization of conjugated enynamides. The reaction could be carried out under relatively mild condition. In presence of a cationic gold catalyst bearing an N‐heterocyclic carbene ligand, enynamides derived from tryptamine react with pyridine N‐oxide, leading to the formation of a variety of tetracyclic spiroindolines in a stereoselective manner.