Measurement of the barrier to inversion of configuration in acyclic phosphite triesters
作者:Joshua A. Mukhlall、William H. Hersh
DOI:10.1016/j.ica.2010.11.022
日期:2011.4
Abstract Synthesis of three acyclic chiral phosphites is reported, in the form of dithymidine phosphite triesters. These diastereomerically pure P-stereogenic phosphites undergo epimerization at a measurable rate at 150 °C. When the alcohols on the deoxyribose moieties are protected as acyls, decomposition is minimized and by computer fitting, rate constants for epimerization can be extracted. These
摘要报道了以亚磷酸二胸苷三酯的形式合成了三种无环手性亚磷酸酯。这些非对映异构纯的P-立体异构亚磷酸酯在150°C下以可测量的速率发生差向异构。当脱氧核糖部分上的醇被保护为酰基时,分解作用降到最低,并且通过计算机拟合,可以提取差向异构化的速率常数。这些允许首次计算亚磷酸三酯中构型转化的障碍,从而给出ΔG†(150°C)= 33.0±0.2 kcal mol-1,与膦的转化障碍相当。