The reaction of 1-acyl-3,5-dimethylpyrazoles 1 with CN compounds was kinetically controlled with syn stereoselectivity through a lithium enolate intermediate using lithium diisopropylamide. In contrast, the anti stereoselective reaction of 1 was caused by the action of diisopropylethylamine in the presence of magnesiumbromide under the thermodynamic control. Reaction of 2-acyl-3-phenyl-l-menthopyrazoles