The reactions of 2-methylimidazoline with excess benzoylchlorides under mild conditions generated N,N′-diacyl-β-keto cyclic ketene-N,N′-acetals. Conversely, the corresponding reactions of 1,2-dimethylimidazoline under the same conditions stereoselectively formed the ring-opened (Z)-vinyl benzoates. The latter reactions feature the formation of carbon-carbon bonds, carbon-nitrogen bonds, and carbon-oxygen