铜催化二羟基乙酸、胺和炔三组分脱羧偶联反应的机理

用密度泛函方法,研究铜催化二羟基乙酸、胺和炔三组分脱羧偶联反应的机理.通过计算实验提出的反应机理,给出并计算新的反应机理:二羟基乙酸与胺原位生成的亚胺盐,先配位到催化剂的铜中心发生脱羧反应,再进行端炔配位和插入、质子化、亲核加成、配体交换等步骤.理论计算结果表明,该机理的决速步骤为端炔插入,反应能垒为129.8kJ/mol,与实验反应温度为110℃的结果一致.

Mechanism of Copper Catalyzed Three-Component DecarboxylativeCoupling Reaction of Glyoxylic Acid,Amine and Alkyne

The author studied the mechanism of Cu catalyzed three\|component decarboxylative coupling reaction of glyoxylic acid, an amine and an alkyne by using the density functional theory methods. First, the reaction mechanism proposed in experiments was calculated, and then a new reaction mechanism was proposed and calculated involving the coordination of the iminium salt, in situ formed from the glyoxylic acid and the amine, decarboxylation, alkyne coordination and insertion, protonation, nucleophilic addition, ligand exchange steps. The results of theoretical calculation show that the rate determining step of the mechanism is the insertion of the alkyne, and the energy barrier of reaction is 129.8 kJ/mol, which is in agreement with the result of experimental reaction temperature of 110 ℃.