Iridium-catalyzed ring-opening reactions of unsymmetrical oxabenzonorbornadienes with water and alcohol nucleophiles

Abstract

The iridium-catalyzed ring-opening reaction of unsymmetrical oxabenzonorbornadienes (OBD) with water and alcohol nucleophiles is reported, with the effects of various C1-substituents explored. Electron-donating alkyl groups lead entirely to the substituted naphthol derivatives in excellent yields while substitution of the C1 position for electron-withdrawing groups afforded ring-opened products in fair to excellent yields with excellent regioselectivity. The reaction was demonstrated to be highly regioselective for the C2 position with no C3 regioisomer observed in all cases. A proposed mechanism for the formation of C2 regioisomeric ring-opened products has been included.