Mechanistic Studies on the Rearrangement of 1‐Alkenyl‐2‐alkynylcyclopropanes: From Allylic Gold(I) Cations to Stable Carbocations

Abstract

An allylic gold(I) cation, proposed as key intermediate in the gold-promoted rearrangement of 1,5-enynes bearing a fixed conformation, has been detected and characterized by NMR spectroscopy. Moreover, its participation in the overall transformation was confirmed. Computational studies indicate that the gold-catalyzed transformation occurs through an uncommon rearrangement. Additionally, this study led us to isolate and characterize a stable homoantiaromatic carbocation.