Cobalt(III)-Catalyzed Selective β-C(sp ² )–H Alkynylation of Acyclic Enamides with Bromoalkynes

A cobalt(III)-catalyzed selective β-C(sp²)-H alkynylation of acyclic enamides with easily accessible bromoalkynes has been successfully achieved. The reaction has a broad substrate scope as well as a good functional group tolerance. This protocol represents a practical route to the synthesis of alkynyl-substituted enamides. In addition, mechanistic experiments suggest that cobalt(III)-catalyzed β-C(sp²)-H activation is related to the critical step.