Highly selective catalytic transfer hydrodeuteration of cyclic alkenes
作者:Samuel J. Hintzsche、Zoua Pa Vang、Emanuel Rivera Torres、Mykaela Podoski、Joseph R. Clark
DOI:10.1002/jlcr.4015
日期:2023.3
alkenes, which enables the synthesis of chromans, quinolinones, and tetrahydronaphthalenes that are precisely deuterated at the benzylic position. We also demonstrate the ability to place one deuterium atom at the homobenzylic site of these scaffolds with high regioselectivity by swapping transfer reagents for their isotopic analogs. Furthermore, examples of chemoselective transfer hydrogenation and transfer
Competition H(D) Kinetic Isotope Effects in the Autoxidation of Hydrocarbons
作者:Hubert Muchalski、Alexander J. Levonyak、Libin Xu、Keith U. Ingold、Ned A. Porter
DOI:10.1021/ja511434j
日期:2015.1.14
both the primary and secondary isotopeeffects for symmetrical substrates by the use of NMR. Intramolecular competition reactions were carried out on substrates having an increasing number of deuterium atoms at symmetry-related sites. Products that arise from peroxyl radical abstraction at each position of the various substrates reflect the competition rates for H(D) abstraction. The primary KIE for
氢原子转移是许多重要自由基链序列的核心。我们在此报告了一种使用 NMR 测定对称底物的初级和次级同位素效应的方法。在对称相关位点具有越来越多氘原子的底物上进行分子内竞争反应。在各种底物的每个位置上由过氧自由基抽象产生的产物反映了 H(D) 抽象的竞争率。四氢化萘自氧化的主要 KIE 被确定为 15.9 ± 1.4,该值超过了 H(D) 零点能量差异预测的最大值 (∼7),强烈表明过氧自由基对 H 原子的夺取发生在大量的量子力学隧道效应。