Gold-Catalyzed Spirocyclization of Activated Alkynes with Organoiodides: Access to 3-Arylated, 3-Alkenylated, and 3-Alkynylated Spiro[4.5]trienones

Abstract

Herein, we report the gold-catalyzed spirocyclization of activated alkynes with organoiodides through ligand-enabled gold redox catalysis. The reaction proceeds smoothly under mild conditions and without the need for an external oxidant, affording a series of 3-arylated, 3-alkenylated, and 3-alkynylated spiro[4.5]trienones in good to excellent yields. This transformation exhibits a broad substrate scope, good functional group tolerance, and compatibility with heteroaromatic systems. The (P,N) ligand MeDalphos-facilitated gold-catalyzed process provides a new strategy for the synthesis of 3-substituted spiro[4.5]trienones. Furthermore, mechanistic investigations, including NMR and mass spectrometric studies, strongly support the proposed reaction mechanism.