<i>meta</i> C–H Arylation of Electron-Rich Arenes: Reversing the Conventional Site Selectivity
作者:Luo-Yan Liu、Jennifer X. Qiao、Kap-Sun Yeung、William R. Ewing、Jin-Quan Yu
DOI:10.1021/jacs.9b07887
日期:2019.9.18
report the first catalytic system that effectively performs meta C-H arylation of a variety of alkoxy aromatics including 2,3-dihydrobenzofuran and chromane with exclusive meta site-selectivity, thus reversing the conventional site selectivity governed by native electronic effects. The identification of an effective ligand and modified norbornene (NBE-CO2Me), as well as taking advantage of the statistics
在不使用导向基团的情况下控制 CH 活化的位点选择性仍然是一个重大挑战。虽然由相互排斥的吡啶型配体调节的 Pd(II) 催化剂已被证明有利于芳烃相对富电子的碳中心,但逆转选择性以有利于相对缺电子位置的钯化作用是不可能的。在这里,我们报告了第一个催化系统,该系统有效地对包括 2,3-二氢苯并呋喃和色烷在内的各种烷氧基芳烃进行间位 CH 芳基化,具有独特的间位选择性,从而逆转了由天然电子效应控制的传统位点选择性。有效配体和改性降冰片烯 (NBE-CO2Me) 的鉴定,