Halotrifluoromethylation of 1,3-Enynes: Access to Tetrasubstituted Allenes.

A highly regioselective copper-catalyzed 1,4-chloro- and bromotrifluoromethylation of 1,3-enynes has been presented for the first time, which affords an efficient transformation to access halo- and CF3-containing tetrasubstituted allene derivatives with good to excellent yield. This protocol is practical and convenient, in which a wide range of functional groups are compatible. Applications of this method for the gram-scale preparation and late-stage functionalization of biologically active molecules are also demonstrated.