Cyclic alkenenitriles: Chemoselective oxonitrile cyclizations

Potassium tert-butoxide triggers the chemoselective cyclization between nitrile anions and remote, enolizable carbonyl groups, despite the acidity difference favoring enolate formation and addition to the nitrile group. Domino deprotonation, cyclization, and dehydration efficiently transform a diverse array of omega-oxonitriles into carbocyclic and heterocyclic five- and six-membered alkenenitriles in a single synthetic operation.