Copper-Catalyzed Syntheses of Multiple Functionalizatized Allenes via Three-Component Reaction of Enynes

A copper-catalyzed three-component reaction of cyclobutanone oxime esters and 1,3-enynes in the presence of TMSCN or TMSCF3 has been developed. This mild protocol enjoys a broad substrate scope tolerating many functional groups, providing a facile access to 1,7-double-functionalized allenes, which are difficult to prepare. The allenyl nitrile products may be easily transformed into allenoic acid derivatives and stereodefined tetrasubstituted alkenes, demonstrating their potentials as platform molecules in synthesis. A mechanism has been proposed on the basis of mechanistic studies.