Rhodium-Catalyzed Intermolecular [2+2] Cycloaddition of Terminal Alkynes with Electron-Deficient Alkenes

The first catalytic intermolecular [2 + 2] cycloaddition of terminal alkynes with electron-deficient alkenes is reported. The reaction proceeds with an 8-quinolinolato rhodium/phosphine catalyst system to give cyclobutenes from various substrates having polar functional groups in high yields with complete regioselectivity.