C2-Functionalization of 1-Substituted Imidazoles with Aldehydes and Electron-Deficient Acetylenes: A Novel Three-Component Reaction

A novel three-component reaction between 1-substituted imidazoles, aldehydes, and electron-deficient acetylenes proceeds under mild conditions (20-25 degrees C, no catalyst, no solvent) to form an unknown family of C2-functionalized imidazoles in up to 74 % yield, the function constituting a push-pull combination of enol ether and acrylic moieties. In the case of cyanophenylacetylene, the function is built up stereospecifically to have the (Z) configuration. The interaction presumably occurs via zwitterion and carbene intermediates. The results contribute to basic imidazole and acetylene chemistry and open a shortcut to promising drug candidates.