Mechanism and kinetics of Horner–Wadsworth–Emmons reaction in liquid–liquid phase-transfer catalytic system
作者:Qiangqiang Zhao、Jie Sun、Fuqiang Li、Jinxin He、Baojiang Liu
DOI:10.1016/j.molcata.2015.01.031
日期:2015.5
Liquid–liquid phase-transfer catalytic (LL-PTC) system suitable for symmetric distyryl compounds could not be used to synthesize asymmetric derivates. Relatively low value, the time-dependence of the interfacial tension with only phosphonate in the organic phase and high background reaction rate demonstrated that “weakly acidic” phosphonate was adsorbed on the interfacial layer and deprotonated by
适用于对称二苯乙烯基化合物的液相-液相转移催化(LL-PTC)系统不能用于合成不对称衍生物。相对低的值,与仅膦酸酯的界面张力的时间依赖性在有机相和高背景的反应速率表明,“弱酸性”膦酸酯被吸附在界面层上,并通过过量“裸露的”去质子化的OH -无需催化剂的帮助。相转移催化剂参与了碳负离子的转移过程,并加速了成键反应。但是,在该PTC系统中,碳负离子对的分布区域取决于催化剂的使用,其机理将从界面机理转变为萃取机理。因此,提出了吸附,去质子,离子交换反应,分布和键形成反应的机理,并建立了动力学模型。活化能和催化活性对亲脂性和可及性参数的依赖性也支持了所提出的机理。