论文部分内容阅读
取代基对分子反应中心的影响,除了通过电子效应和立体效应以外,还能在分子内发生另一种直接作用,即分子内某些取代基可与反应中心作用,形成过渡态或环形中间体而影响某一反应。这类取代基一般带有π电子或未共享电子对,在分子内充当亲核试剂,发生分子内的亲核取代。这种在同一分子内,亲核的取代基参与反应中心取代反应的现象。邻基参与在有机化学中,特别是在亲核取代,消除和重排中普遍存在,它对反应速度和反应产物等影响很大,是有机化学中一种较重要的效应。
Substituents on the reaction center of the molecule, in addition to the electronic effect and the three-dimensional effect, but also in the molecule another direct role, that is, some of the molecules within the molecule can react with the reaction center, the formation of transition state or ring intermediate Affect a response. Such substituents usually have π electrons or unshared electron pairs, act as nucleophiles in the molecule, and undergo intramolecular nucleophilic substitution. This in the same molecule, the nucleophilic substituents participate in the reaction center substitution reaction phenomenon. Ortho-based participation in organic chemistry, especially in the nucleophilic substitution, elimination and rearrangement of ubiquitous, it has a great impact on the reaction rate and reaction products, is a more important organic chemistry.