Regioselective Functionalization of Enamides at the α‑Carbon via Unsymmetrical 2‑Amidoallyl Cations

A new method to functionalize enamides
via an intermediacy of unsymmetrical
2-amidoallyl cations is reported. Generated under mild Brønsted
acid catalysis, these reactive species were found to undergo addition
with various nucleophiles at the less substituted α-carbon to
produce highly substituted enamides in high yields with complete control
of regioselectivity.

本研究报道了一种以不对称2-酰胺基烯丙基正离子（unsymmetrical 2-amidoallyl cations）为中间体实现烯酰胺（enamides）官能化的新方法。该活性物种在温和的布朗斯特酸（Brønsted acid）催化下生成，实验发现其可与各类亲核试剂在取代度更低的α-碳原子处发生加成反应，最终以高产率得到高度取代的烯酰胺产物，并实现了完全的区域选择性控制。