Metal-Free Cross-Dehydrogenative C–O Coupling of Carbonyl Compounds with <i>N</i>-Hydroxyimides: Unexpected Selective Behavior of Highly Reactive Free Radicals at an Elevated Temperature
作者:Igor B. Krylov、Elena R. Lopat’eva、Alexander S. Budnikov、Gennady I. Nikishin、Alexander O. Terent’ev
DOI:10.1021/acs.joc.9b02656
日期:2020.2.21
N-hydroxyphthalimide drastically affects the oxidative properties of t-BuOOt-Bu by intercepting the t-BuO• radicals with the formation of phthalimide-N-oxyl radicals, a species responsible for both hydrogen atom abstraction from the CH reagent and the selective formation of the C-O coupling product by selective radical cross-recombination. The practical applicability of the developed method was exemplified by the
N-羟基酰亚胺与酮,酯和羧酸的交叉脱氢CO偶联是通过使用二叔丁基过氧化物作为自由基源和脱氢剂来实现的。所提出的方法在实验上很简单,并且证明了对于具有挑战性的CH底物(例如未活化的酯和羧酸)具有出色的效率。结果表明,N-羟基邻苯二甲酰亚胺通过拦截t-BuO•自由基而形成邻苯二甲酰亚胺-N-氧基自由基,从而极大地影响t-BuOOt-Bu的氧化性能。通过选择性自由基交叉重组选择性形成CO偶联产物。