The E1cb route for ester hydrolysis; volumes of activation as an additional criterion of mechanism
作者:Neil S. Isaacs、Tariq S. Najem
DOI:10.1039/p29880000557
日期:——
of esters which possess an acidic proton at the α or vinylogous position can, in principle, hydrolyse by the E1cb route via a ketenoid intermediate. To the kinetic evidence for such a mechanism in the hydrolyses of 4-hydroxybenzoates, malonates, acetoacetates and fluorenecarboxylates is now added the further criterion of volumes of activation. Values of ΔV‡ for reactions proceeding by the E1cb route
原则上,在α或乙烯基位置具有酸性质子的酯的水解可以通过酮类中间体通过E 1cb途径进行水解。对于这种在4-羟基苯甲酸酯,丙二酸酯,乙酰乙酸酯和芴羧酸酯水解中的机理的动力学证据,现在增加了活化体积的进一步标准。Δ的值V ‡为反应由出发Ë 1CB路线是正和对比度与由更通常与水解相关的负值乙AC 2机构。