A novel copper-catalyzed [3+2] cycloaddition reaction with concomitant in situ generation
of benzoylacrylonitriles and nitrile imines from phenacylmalononitriles and hydrazonoyl
chlorides, respectively, is reported. The reaction was performed using copper(I) chloride
as catalyst and N-methylimidazole as a clean complexing agent/weak base to afford the functionalized
4-benzoyl-5-cyanopyrazoles in moderate to good yields and excellent regioselectivity
under ambient conditions. This method provides rapid access to a wide range of highly
functionalized 4-benzoyl-5-cyanopyrazoles.
Key words
4-benzoyl-5-cyanopyrazoles - copper catalysis - [3+2] cycloaddition - phenacylmalononitrile
- hydrazonoyl chloride
