1,5-HYDRIDE SHIFTS IN VINYL CATION INTERMEDIATES PRODUCED UPON THE ACYLATION OF ACETYLENES

The acylation of alkynes with a variety of cyclohexanecarbonyl cations under nonnucleophilic conditions has been investigated. A facile intramolecular 1,5-hydride shift from the β-carbon of the acylating agent to the initially formed vinyl cation intermediate is a common feature of all these reactions. The subsequent reactions of the rearranged carbenium ion are sensitive to the structure of the acylating agent and one pathway available to this carbenium ion involves a 1,2-acyl migration. The utilization of this process is demonstrated in the synthesis of certain 1,2-adamantane systems. © 1979, American Chemical Society. All rights reserved.