Nickel/Lewis Acid-Catalyzed Carbocyanation of Alkynes Using Acetonitrile and Substituted Acetonitriles

Nickel/Lewis acid dual catalysis is found to effect the carbocyanation reaction of alkynes using acetonitrile and substituted acetonitriles to give a range of variously substituted acrylonitriles. The addition of propionitrile across alkynes is also demonstrated briefly to give the corresponding ethylcyanation products in good yields, whereas the reaction of butyronitrile gives significant amounts of hydrocyanation products due possibly to β-hydride elimination of a propyinickel intermediate. The reaction of optically active α-phenylpropionitrile suggests a reaction mechanism that involves oxidative addition of a C-CN bond with retention of its absolute configuration.