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用密度泛函理论B3LYP方法对双官能团离子液体[Promim]+[CF3CO2]-支撑丙酮与邻-硝基苯甲醛不对称aldol反应进行了研究.结果表明,该离子液体的脯胺酸和咪唑基团一起对反应产生催化作用.整个反应包括:丙酮的羰基与脯胺酸基团的胺基间的亲核加成反应,咪唑2-位氢参与的脱水反应生成亚胺IM1-2,丙酮甲基脱氢反应生成烯胺I M1-3,苯甲醛与烯胺的亲核加成反应,水加成反应和催化剂再生反应.第一步骤是速率控制步骤,产物羟基位碳原子的手性在苯甲醛与烯胺的亲核加成反应中产生.另外,在咪唑环2-位氢参与的脱水反应中生成的水分子辅助丙酮甲基脱去α-氢生成烯胺.苯甲醛邻位吸电子基团能降低醛基碳原子的电子密度,增强醛基碳原子的亲电性,从而增强反应物活性.离子液体[Promi m]+[CF3CO2]-产生的溶剂化效应使反应势垒降低(除开催化剂再生步骤).
The asymmetric aldol reaction of [Promim] + [CF3CO2] -supported acetone with o-nitrobenzaldehyde was studied by density functional theory B3LYP method. The results showed that the proline and imidazolyl The reaction together catalyzed the reaction.The reaction includes: the nucleophilic addition reaction between the carbonyl group of acetone and the amine group of proline group, the dehydration reaction of 2-position hydrogen of imidazole to imine IM1-2 and acetone Radical dehydrogenation of enamine I M1-3, nucleophilic addition reaction of benzaldehyde with enamine, water addition reaction and catalyst regeneration reaction.The first step is the rate control step, Benzaldehyde and enamine nucleophilic addition reaction generated.In addition, 2-position in the imidazole ring dehydration reaction of water generated by the auxiliary acetone methyl off α-hydrogen enamine. Benzaldehyde ortho-absorption The electron group can reduce the electron density of the aldehyde group carbon atom and enhance the electrophilicity of the aldehyde carbon atom to enhance the reactant activity.The solvation effect of [Promi m] + [CF3CO2] - (Except for the catalyst regeneration step).