摘要/Abstract

报道了镁-双噁唑啉络合物体系催化的TMSCN与3,5-二甲基-N-α,β-不饱和酰基吡唑的不对称共轭氰化反应. 考察了BOX配体结构、配体与金属比例、温度、溶剂等对反应的影响. 研究结果表明, 使用双苄基取代的双噁唑啉配体与二丁基镁(物质的量比为2∶1)在1,2-二氯乙烷中原位生成手性催化剂, 催化剂用量为10 mol%, 反应温度为–32 ℃, 不对称共轭氰化反应催化效果最佳. 将上述催化方法应用于一系列3,5-二甲基-N-α,β-酰基吡唑衍生物, 绝大部分以90%以上的产率和中等以上的对映选择性获得相应的目标产物.
关键词: 双噁唑啉, 三甲基氰硅烷, 3,5-二甲基-N-α,β-不饱和酰基吡唑, 不对称共轭氰化
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


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