Dual Iminium- and Lewis Base Catalyzed Morita-Baylis-Hillman Reaction on Cyclopent-2-enone

The application of iminium catalysis to the challenging Morita–Baylis–Hillman reaction on cyclopenten-2-one leads to the corresponding allylic alcohols in excellent yields. Experimental evidence shows that secondary amines act as co-catalysts activating the enone moiety towards the nucleophilic attack at the β-position by DABCO as the Lewis base catalyst, resulting in an augmented nucleophilic character towards the reaction with aldehydes.