Catalyst-Free Regio- and Stereoselective C(sp²)-H Chlorination of Enamides at Room Temperature

We disclose herein a catalyst-free, room-temperature protocol for the highly regio- and stereoselective alkenyl C(sp²)-H chlorination of diverse enamides with commercially available, inexpensive N-chlorosuccinimide (NCS) as the electrophilic chlorinating reagent under exceedingly mild conditions. This operationally simple approach features a remarkably broad substrate scope and accommodates excellent functional group tolerance, affording a diverse range of synthetically valuable geometrically defined β-chlorinated enamides in high yields with an exclusive E configuration.