In this Communication, we report an unprecedented β‐regioselective radical inverse hydroboration (compared with ionic hydroboration) of α,β‐unsaturated amides with NHC‐BH3 enabled by photoredox catalysis. Density functional theory (DFT) calculations show that the unique photoredox cycle is a key factor to control the β‐regioselective radical hydroboration, by lowering the energy barrier in comparison
Visible‐Light‐Induced Radical Defluoroborylation of Trifluoromethyl Alkenes: An Access to
<i>gem</i>
‐Difluoroallylboranes
作者:Guojun Chen、Liling Wang、Xiaozu Liu、Peijun Liu
DOI:10.1002/adsc.202000257
日期:2020.7.29
A photoredox‐catalyzed defluoroborylation of trifluoromethyl alkenes with N‐heterocycliccarbene boranes is described for the synthesis of gem‐difluoroallylboranes. This protocol exhibits a broad substrate scope and good functional group compatibility, which enables the late‐stage functionalization of structurallycomplex compounds. Further transformations of the defluoroborylation products to valuable
The first catalytic inverse hydroboration of imines with N‐heterocyclic carbene (NHC) boranes has been realized by means of cooperative organocatalysis and photocatalysis. This catalytic combination provides a promising platform for promoting NHC‐boryl radical chemistry under sustainable and radical‐initiator‐free conditions. The highly important functional‐group compatibility and possible application
Hydroboration of Arynes with N-Heterocyclic Carbene Boranes
作者:Tsuyoshi Taniguchi、Dennis P. Curran
DOI:10.1002/anie.201408345
日期:2014.11.24
Arynes were generated in situ from ortho‐silyl aryl triflates and fluoride ions in the presence of stable N‐heterocyclic carbeneboranes (NHCBH3). Spontaneous hydroboration ensued to provide stable B‐aryl‐substituted NHC‐boranes (NHCBH2Ar). The reaction shows good scope in terms of both the NHC‐borane and aryne components and provides direct access to mono‐ and disubstituted NHC‐boranes. The formation
Borylative Radical Cyclizations of Benzo[3,4]cyclodec‐3‐ene‐1,5‐diynes and N‐Heterocyclic Carbene‐Boranes
作者:Takashi Watanabe、Daisuke Hirose、Dennis P. Curran、Tsuyoshi Taniguchi
DOI:10.1002/chem.201700689
日期:2017.4.24
Borylative radical cyclization of benzo[3,4]cyclodec‐3‐ene‐1,5‐diynes to provide 5‐borylated 6,7,8,9‐tetrahydrobenzo[a]azulenes has been developed. The experimental results suggest that the reaction proceeds by a radical chain mechanism, in which di‐tert‐butyl hyponitrite (TBHN) works as a good radical initiator to form borylradicals from N‐heterocyclic carbene–boranes (NHC‐boranes). The present reaction
已开发出苯并[3,4] cyclodec-3-烯-1,5-二炔的硼酸自由基环化反应,以提供5硼酸化的6,7,8,9-四氢苯并[ a ] azulenes。实验结果表明,反应是通过自由基链机理进行的,其中二叔丁基亚硝酸盐(TBHN)作为良好的自由基引发剂,可从N杂环卡宾-硼烷(NHC-硼烷)形成硼自由基。本反应是罕见的模型,其说明了向炔烃中加硼基。