Copper-Catalyzed Acyloxycyanation of Alkynes with Acetonitrile: Regioselective Construction of Cyclic Acrylonitriles by 6-endo or 5-exo Cyclization

An efficient difunctionalization of alkynes by tandem iodolactonization and copper-catalyzed cyanation using acetonitrile as a cyanating reagent is reported for the first time. This approach can afford cyano-containing isocoumarin- or phthalide- derivatives in good yields by careful choice of the carboxylate nucleophiles and electrophilic iodine sources. Thus, an acyloxycyanation strategy can be achieved in good yields and high regioselectivity of either 6-endo or 5-exo cyclization products.