Copper-Catalyzed Borylstannylation of Alkynes with Tin Fluorides

Tin fluorides were found to be suitable electrophiles for the copper-catalyzed borylstannylation of terminal alkynes with bis(pinacolato)diboron to afford cis-vic-boryl(stannyl)alkenes straightforwardly. A fluorine atom proved to play a pivotal role in generating a key catalytic intermediate, a borylcopper species, both in the induction period and in the sigma-bond metathesis step.