Acid-catalysed hydrolysis of methoxy-substituted trityl trifluoroethyl ethers: a kinetic and computational investigation of leaving group effects
作者:Moisés Canle López、Ibrahim Demirtas、Howard Maskill、Masaaki Mishima
DOI:10.1002/poc.1332
日期:2008.7
corresponding free energies at 25°C for the dissociation of the specifically solvated ions CH3 (YH = MeOH and CF3CH2OH, n = 1; H2O, n = 2; and NH3, n = 3) have been calculated at the B3LYP/6-31+G* level. Corresponding gas phase calculations have also been carried out for Ph3C (YH = H2O, n = 2; MeOH, n = 1; CF3CH2OH, n = 1 and NH3, n = 3) and, in addition, structures for these solvated ions with (YH = H2O
已经制备了三苯甲基三氟乙基(TFE)醚及其4-甲氧基,4,4'-二甲氧基-和4,4',4''-三甲氧基取代的类似物;二甲氧基和三甲氧基化合物在25°C下以恒定的离子强度= 1 mol dm -3进行酸催化的水解。单甲氧基化合物反应性较低,母体三苯甲基类似物显示出最小的反应性。使用目前报道的和文献报道的动力学结果,质子化底物的p K a值,已经确定了涵盖12个数量级的一级速率常数,用于11种质子化二甲氧基三苯甲基衍生物DMTrYH +的杂解/离解,其中YH = H 2 O,CF 3 CH 2 OH,ArNH 2和RNH 2。这些速率常数的对数与核键YH的共轭酸(Y )的p K a值之间具有良好的相关性。于25°C时解离特定溶剂化离子CH 3的焓和相应的自由能(YH = MeOH和CF 3 CH 2 OH,n = 1; H 2 O,n = 2;和NH 3,n = 3)是以B3LYP / 6-31