N-heterocyclic carbene catalyzed aza-Morita-Baylis-Hillman reaction of cyclic enones with N-tosylarylimines.

N-Heterocyclic carbenes (NHCs) prove to be efficient catalysts for the aza-Morita-Baylis-Hillman (aza-MBH) reaction of cyclopent-2-en-1-one or cyclohex-2-en-1-one with a variety of N-tosylarylimines to give the aza-MBH adduct in high yields. Crossover experiments show NHC can add to N-tosylarylimines in a reversible manner, which allows the addition of NHC to cyclic enones and thus catalyzes the aza-Mortia-Baylis-Hillman reaction.