Access to α-all-carbon quaternary amides through the hydroamidation of allenes using DIBAL-H and isocyanates

Abstract

A straightforward and highly selective hydroamidation process involving the copper-catalyzed hydroalumination of allenes, followed by allylation with isocyanates, is presented. This methodology offers a direct and efficient route to the construction of challenging α-all-carbon quaternary centers within β,γ-unsaturated acyclic amides, providing high yields (up to 99%) with excellent regio- and E-stereoselectivities. The reaction operates under mild and simple conditions and accommodates a wide range of readily accessible di- or tri-substituted allenes and isocyanates. To demonstrate the practicality of this approach, we conduct a gram-scale reaction to produce the desired α-quaternary amide and showcase its versatility by synthesizing six- and seven-membered lactams. These results highlight the synthetic value of this methodology.