The asymmetric conjugate cyanation reaction of TMSCN with 3,5-dimethyl-N-α,β-unsaturated acylpyrazole catalyzed by magnesium-bisoxazoline complex was studied. The effects of BOX ligand structure, ligand to metal ratio, temperature, solvent, etc. on the reaction were investigated. The results showed that when bis-benzyl substituted bisoxazoline ligand and dibutylmagnesium (molar ratio 2∶1) were used to generate chiral catalyst in situ in 1,2-dichloroethane, the amount of catalyst was 10 mol%, and the reaction temperature was –32 ℃, and the catalytic effect of asymmetric conjugate cyanation reaction was the best. The catalytic method above was applied to the conjugate cyanation reaction of a series of 3,5-dimethyl-N-α,β-unsaturated acyl pyrazole derivatives, most of the corresponding target products could be obtained with more than 90% yield and moderate to good enantioselectivities.

Key words: bisoxazoline, TMSCN, 3,5-dimethyl-N-α,β-unsaturated acyl pyrazole, asymmetric conjugate cyanation