3-Borylbenzynes were generated in situ from 6-boryl-2-iodophenyl trifluoromethanesulfonates using i-PrMgCl·LiCl and applied to Diels–Alder reactions with substituted furans and pyrroles. The reactions allowed good functional group compatibility and produced the cycloadducts in high yields with high distal selectivities. Effective conversion of the boryl group of the products was achieved. A series