[2+2]环加成反应机理的理论研究

2+2]环加成反应是有机化学中非常重要的一类反应,其机理的研究一直是实验和理论工作者关注的课题之一。本文从理论的角度综述了三类2+2]环加成反应的反应机理,即简单烯烃或炔烃参与的环加成反应、累积双键体系参与的环加成反应以及稀土钍化合物参与的环加成反应, 得出对于简单的烯烃或炔烃之间的环加成反应一般是按双自由基机理进行,而其他两类反应主要按协同或两性离子方式进行,并且从前线分子轨道作用理论角度分析了产生不同反应机理的原因。

Theoretical Studies on the Mechanisms of [2+2] Cycloaddition Reactions

2 + 2] cycloaddition reaction is one type of the most important reactions in the field of organic chemistry,and the mechanisms of 2 + 2] cycloaddition reactions are always hot topic both for experimental and theoretical researchers.In this paper,three types of 2 + 2] cycloaddition reactions,including that of simple olefins or alkynes,cumulenes,Th compounds,have been classified and reviewed.The obtained results indicate that the cycloaddition reactions involving simple olefins or alkynes are proceeding in diradical mechanism generally,and the others are proceeding in either concerted or zwitterion mechanism.All of which have been elucidated with frontier molecular orbital interactions.