摘要
基于密度泛函理论研究了氯代苯基硫脲催化的硝基苯乙烯与硫叶立德的Michael加成反应,确定了控制反应立体选择性的C―C键形成步骤的过渡态结构,计算了过渡态的相对能量和反应势垒,弄清了硫脲催化的微观反应机理,探讨了硫脲催化性能的微观本质.结果表明,反应有利于反式Michael加成产物的形成,硫脲在反应中作为质子给体,首先与质子受体硝基苯乙烯形成双氢键配合物,通过授受体间的电荷转移活化硝基苯乙烯的β-C原子增强其亲电性,有利于硫叶立德的亲核进攻.
Using density functional theory calculations,we have studied the 1-（2-chlorophenyl）-2-thiourea catalyzed reaction of nitrostyrene with a typical sulfur ylide to understand the Michael addition mechanism. Transition state structures for the C―C bond-forming step controlling the stereoselectivity of the reaction have been identified and their relative stabilities evaluated.The role of the catalyst in the reaction has also been determined.The calculated results show that the formation of the anti-product is energetically more favorable than that of the syn-product.Furthermore,the catalyst（proton donor）promotes the reaction by forming a double hydrogen-bonded complex with nitrostyrene（proton acceptor）,where the charge transfer between the donor and acceptor increases the eletrophilicity of β-C atom of the nitrostyrene,favoring the nucleophilic attack of the sulfur ylide.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2012年第3期561-566,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20873076)
教育部博士点基金(200804220009)资助项目~~
