摘要
研究了以铜化合物催化重氮乙酸乙酯与烯烃的环丙烷化反应,首次计算了反应关键中间体铜-卡宾的环丙烷化选择性P及该中间体的解离常数K,结果表明:1.反应体系中可能存在着铜-卡宾与游离卡宾的平衡;2.P、K与所用的催化剂有关。使用不同的催化剂,温度对反应选择性的影响也不同,对以上结果进行了理论探讨。
Copper complexes are used for catalyzing the cyclopropanation of ethyl diazoacetate with 2,5-dimethyl-2, 4- hexadiene. The reaction selectivity of ethyl diazoacetate is seriously affected by the catalyst amount and the reaction temperature. The cyclopropanation selectivities and dissociation constants of copper-carbene formed from ethyl diazoacetate and Cu(Salad )2. Cu (O2CCCl3)2 are calculated for the first time. The results show that: 1. there may be an equilibrium between copper-carbene and free carbene; 2. the back-donating π-bond determines the stability of the copper-carbene intermediate; 3. the more stable the intermediate the lower cyclopropanation selectivity, and the less seriously the selectivity is affected by the reaction temperature.
出处
《分子催化》
EI
CAS
CSCD
1992年第5期352-358,共7页
Journal of Molecular Catalysis(China)
关键词
重氮乙酸乙酯
环丙烷化
铜
催化剂
Ethyl diazoacetate, Carbene, Cyclopropanation, Cu catalyst.
