Theoretical Studies on the Mechanism of Mannich Reaction Involving Iminium Salt as Potential Mannich Reagent(4)——Use 2-Methylpropaldehyde as Pseudo-acid Component  

作　　者：翟宇峰 凌月 肖鹤鸣[1] 

机构地区：[1]南京理工大学化学系

出　　处：《分子科学学报》1998年第3期36-41,共6页Journal of Molecular Science

摘　　要：以一个真实的Ｍａｎｎｉｃｈ试剂（ＣＨ３）２Ｎ＋ＣＨ２·Ｃｌ－作为研究对象．根据ＡＭ１方法的计算结果，胺、醛及伪酸在中性和酸性介质中的经典Ｍａｎｎｉｃｈ反应的关键步骤的活化能分别为３９０．０和３２１．８ｋＪ／ｍｏｌ．而由新Ｍａｎｎｉｃｈ试剂参与的Ｍａｎｎｉｃｈ反应的关键步骤活化能则为２７８．６ｋＪ／ｍｏｌ．因此新Ｍａｎｎｉｃｈ试剂可以提高反应速率，还分析了新Ｍａｎｎｉｃｈ试剂能降低反应活化能的原因．此外还讨论了另一种可大大降低活化能的新Ｍａｎｎｉｃｈ反应机理本文是研究Ｍａｎｎｉｃｈ反应机理的系列文章之一．This paper is one of the series reports of theoretical researches on the mechanism of Mannich reaction using the iminium salt as potential Mannich reagent .Unlike the former works, a real Mannich reagent (CH 3) 2N + CH 2·Cl - was taken into account. According to the results of AM1 calculations, the activation energies of key steps in conventional Mannich reactions between ammonia, formaldehyde and acetaldehyde in neutral and acidic media are 390.0 kJ/mol and 321.8 kJ/mol respectively. The activation energy of the key step in Mannich reaction which contains the potential Mannich reagent is 278.6 kJ/mol. Thus the potential Mannich reagent can enhanc the rate of reaction . The reasons for this result are discussed . Another different conjectured mechanism of potential Mannich reagent which can reduce the activation energy considerably is also discussed.

关 键 词：Mannich反应 AM1法 伪酸 活化能 

分 类 号：O643.12[理学—物理化学]