Domino Inverse Electron-Demand Diels-Alder/Cyclopropanation Reaction of Diazines Catalyzed by a Bidentate Lewis Acid

A domino inverse electron-demand Diels-Alder (IEDDA)/cyclopropanation reaction of diazines was discovered by applying electron-rich furans in the bidentate Lewis acid catalyzed IEDDA reaction. This process produces benzonorcaradienes in excellent yields with a low loading of a bidentate Lewis acid catalyst of 2 to 5 mol %. We demonstrate the broad applicability by 20 examples with different dienophiles and a variety of dienes. A detailed mechanism is proposed supported by DFT calculations.