N-Heterocyclic Carbene-Catalyzed Double Michael Addition of Cyano Acetates and Dienones: Diastereoselective Synthesis of Multisubstituted Cyclohexanones and Indanes

The unique Brønsted basic character of N-heterocyclic carbenes (NHCs) has been used to catalyze the double Michael addition between dienones and cyanoacetates.In the presence of 10 mol% NHC, divinyl ketones reacted with cyano acetates to produce multisubstituted cyclohexanones in 60%～89% yields with 5∶1～＞20∶1 dr.Under the same conditions, benzenedi(enones) underwent double Michael addition with cyano acetates or malononitrile to construct multisubstituted indanes in 77%～98% yields and ＞20∶1 dr.