Abstract
A regioselective transition metal-catalyzed cycloisomerization reaction of boron-containing alkynyl epoxides toward C2- and C3-borylated furans has been developed. It was found that the copper catalyst as well as the gold catalyst with more basic triflate counterion favor boryl migration toward C3-borylated furans, whereas employment of the cationic gold hexafluoroantimonate affords C2-borylated furan via a formal 1,2-hydrogen shift.