and nickel catalysts, furnishing five-membered cyclic boryl ethers regioselectively in good yields via 5-exo cyclization. The products were transformed into highly substitutedα,β-unsaturatednitriles via Suzuki–Miyaura coupling to aryl iodides, rhodium-catalyzed conjugative addition to methyl vinyl ketone, and rhodium-catalyzed protodeborylation.