A Resourceful Access to (alpha)-Functionalized Arylhydrazones

Several compounds containing active methylene groups flanked by carbonyl, cyano or nitro groups were reacted with N-nonaflylbenzotriazole (BtNf, 1) at room temperature. An instantaneous reaction took place, which was complete within 10-30 minutes. All active methylene compounds gave hydrazono derivatives by the attack of the carbon nucleophile at the nitrogen in position 2 of the BtNf followed by ring-opening, thus providing a new access to (alpha)-functionalized arylhydrozones.