Synthesis of Functionalized Ketenimines from Hydrazones, Acetylenic Esters, and Alkyl Isocyanides

A simple, efficient one-pot three-component reaction of alkyl isocyanides, acetylenic esters, and hydrazones proceeded at dichloromethane at room temperature afford as highly functionalized ketenimines. The reaction between benzaldehyde derivatives with isatin or benzhydrazide provides hydrazones in good to excellent yields. 1,3-Dipolar intermediates result from alkyl isocyanides to acetylenic esters in the presence of acidic proton, for example, hydrazones proceeded at ketenimines. The functionalized ketenimines caused a suitable substrate for organic compounds. The present procedure carries the advantage that not only is the reaction performed under neutral conditions, but also the substances can be mixed without any activation or catalyst.