1,2-Alkynyl Functionalization of Unactivated Alkenes via Diverse Radical-Triggered Functional Group Migration

Wehave developed a transition-metal-free radical approach for1,2-alkynyl functionalization of unactivated alkenes through the combinationof 3-exo-dig cyclization with alkynyl migration triggeredby in situ-generated diverse radical precursors. This strategy providesa robust toolkit to access a variety of synthetically important & alpha;-functionalizedalkynyl ketones, simultaneously installing densely functionalizedcarbonyl, alkynyl, and other various functional groups into the alkenes.The broad substrate scope, which includes distinctly electron-donatingor electron-withdrawing alkynyl migrating groups, excellent functionalgroup compatibility, and remarkable selectivity make this protocolpractical and attractive.