AbstractA highly regioselective ring opening and stereoselective addition reaction of sulfonylaziridines with cyanoacetylenes promoted by 1,4‐diazabicyclo[2.2.2]octane (DABCO) was investigated. A variety of functionalized (Z)‐enenitriles could be obtained in good yields through regioselective cleavage of carbon‐nitrogen bonds in sulfonylaziridines.magnified image