Regio- and Stereoselective Copper-Catalyzed Borylation-Protodeboronation of 1,3-Diynes: Access to ( Z )-1,3-Enynes.

A facile method to access ( Z )-1,3-enynes is realized via sequential copper-catalyzed regio- and stereoselective borylation-protodeboronation of 1,3-diynes. Pinacolborane, copper(II) acetate, and Xantphos as the ligand efficiently install hydrogen and Bpin in a cis fashion, which is followed by rapid hydrolysis with water. The reaction has wide substrate scope and occurs in a chemoselective fashion.