各种连接的α-硼基乙酸酯的碱性水解提供了未知化合物硼乙酸(BH 2 CH 2 CO 2 H)的第一连接衍生物。用N杂环卡宾,胺和吡啶配体(L)制备了四种一元酸(L-BH 2 CH 2 CO 2 H)和一种二元酸(L-BH (CH 2 CO 2 H)2)。稳定的酸通过X射线晶体学和酸度常数(p K a)测量来表征。它们是所有已知羧酸中酸度最低的。反过来,它们的共轭碱是所有羧酸盐中最强的。
Insertion of Reactive Rhodium Carbenes into Boron–Hydrogen Bonds of Stable N-Heterocyclic Carbene Boranes
作者:Xiben Li、Dennis P. Curran
DOI:10.1021/ja4056245
日期:2013.8.14
available rhodium(II) salts catalyze reactions between NHC-boranes (NHC-BH3) and diazocarbonyl compounds (N2CRCOR'). Stable α-NHC-boryl carbonyl compounds (NHC-BH2-CHRCOR') are isolated in good yields. The reaction is a reliable way to make boron-carbon bonds with good tolerance for variation in both the NHC-borane and diazocarbonyl components. It presumably occurs by insertion of a transient rhodium carbene
Enabling Cyclopropanation Reactions of Imidazole Heterocycles via Chemoselective Photochemical Carbene Transfer Reactions of NHC-Boranes
作者:Ze-Le Chen、Claire Empel、Kun Wang、Pan-Pan Wu、Bao-Gui Cai、Lei Li、Rene M. Koenigs、Jun Xuan
DOI:10.1021/acs.orglett.2c00609
日期:2022.3.25
Herein we report a site-selective cyclopropanation of N-heterocyclic carbene (NHC)-borane complexes via photochemical carbene transfer reactions. By subtle changes to the reaction conditions, this approach can be further extended toward the difunctionalization of NHC-boranes via cyclopropanation and the B–H insertion reaction. Further investigations in photochemical continuous-flow applications and