An unsymmetrical diboron, (pin)B–B(aam), is smoothly added across a carbon–carbon triple bond of various terminal alkynes under platinum catalysis, resulting in the regio- and stereoselective formation of cis-vic-diborylalkenes via B(aam)-installation at the terminal carbon. The use of a highly electron-deficient triarylphosphine ligand, P(BFPy)3, is indispensable for the regiocontrol, and electron-deficiency in ligands has been proven to be closely correlated with the regioselectivity.
