<sup>31</sup>P NMR Spectroscopically Quantified Hydrogen-Bonding Strength of Thioureas and Their Catalytic Activity in Diels-Alder Reactions
作者:Alexander R. Nödling、Gergely Jakab、Peter R. Schreiner、Gerhard Hilt
DOI:10.1002/ejoc.201402871
日期:2014.10
the 31P NMR chemical shifts. A linear correlation between both variables was observed throughout the functionalized thioureas. The 31P NMR probe correlation fared better in comparison to a pKa correlation. Accordingly, the quantification presented herein by using a 31P NMR probe offers an elegant way to estimate the catalytic activity of thiourea catalysts in hydrogen-bond-activated reactions such
通过使用三烷基氧化膦作为 31 P NMR 探针来量化各种常用硫脲催化剂的氢键强度。检查了简单的二芳基硫脲和更复杂的双功能胺和羟基取代的硫脲衍生物。它们的催化活性在 Diels-Alder 反应中测定,获得的准一级速率常数与 31P NMR 化学位移相关。在整个官能化硫脲中观察到两个变量之间的线性相关性。与 pKa 相关性相比,31P NMR 探针相关性表现更好。因此,本文通过使用 31P NMR 探针进行的量化提供了一种优雅的方法来估计硫脲催化剂在氢键活化反应(如 Diels-Alder 反应)中的催化活性。