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最近,在富电子烯烃环丙烷化方面应用超声波取得了一定的效果。但对贫电子烯烃的环丙烷化尚未见报道。我们用超声波研究了原位产生的零价钴与镍催化贫电子烯烃(马来酸二甲酯)与二溴甲烷的环丙烷化反应。结果发现,超声波不但可以加速体系内烯烃络合物的形成,而且能显著加快环丙烷化反应速度,提高反应收率达94％。提供了目前实验室制备1,2-环丙烷二羧酸二甲酯的最简易方法。
Recently, the application of ultrasonic waves in the electronic enrichment of alkenes with cyclopropanation has achieved some effects. However, the cyclopropanation of electron-poor olefins has not been reported yet. We used ultrasound to study the zero-valent cobalt and nickel generated in situ catalyzed cyclopropanation of an electron-poor olefin (dimethyl maleate) with dibromomethane. The results showed that ultrasonic wave can not only speed up the formation of olefin complexes in the system, but also significantly accelerate the cyclopropanation reaction and increase the reaction yield by 94%. The simplest method currently available in the laboratory for preparing dimethyl 1,2-cyclopropanedicarboxylate is provided.