Rhodium-Catalyzed Expeditious Synthesis of Indenes from Propargyl Alcohols and Organoboronic Acids by Selective 1,4-Rhodium Migration over β-Oxygen Elimination

Abstract

An expeditious synthetic route to 1,1-disubstituted indenes from propargyl alcohols and organoboronic acids was developed under rhodium catalysis, and selective 1,4-rhodium migration over β-oxygen elimination was involved as the key step. DPEphos was found to be crucial to promote the transformation, and density functional theory (DFT) calculations indicated that DPEPhos can lower the relative energy of the key intermediate on the 1,4-migration path, leading to the unusual selectivity.