Transition-metal-free PhI(OAc)2-promoted highly selective hydroboration of terminal alkynes under air

A new transition-metal-free PhI(OAc)2-promoted hydroboration reaction of terminal alkynes with bis(pinacolato)diboron has been developed at room temperature under air. A series of vinyl boronates could be conveniently and efficiently obtained in moderate to good yields with good regioselectivity and stereoselectivity as well as favorable functional group tolerance. The key I–B intermediates were first demonstrated in the present reaction system that explains the proposed mechanism.