Relative Reactivity of Stable Ligated Boranes and a Borohydride Salt in Rhodium(II)-Catalyzed Boron–Hydrogen Insertion Reactions
作者:Thomas H. Allen、Dennis P. Curran
DOI:10.1021/acs.joc.6b00091
日期:2016.3.4
Rh(II)-catalyzed B–H insertion reactions with methyl 2-phenyl-2-diazoacetate. Stable α-boryl ester products were isolated by flash chromatography in all cases except for the salt product from cyanoborohydride. All of the substrates were either comparable to or more reactive than 1,4-cyclohexadiene, which is one of the most reactive substrates in C–H insertion reactions. The range of reactivity between
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
N-Heterocyclic Carbene Boryl Iodides Catalyze Insertion Reactions of N-Heterocyclic Carbene Boranes and Diazoesters
作者:Thomas H. Allen、Takuji Kawamoto、Sean Gardner、Steven J. Geib、Dennis P. Curran
DOI:10.1021/acs.orglett.7b01777
日期:2017.7.7
Boron–hydrogen bond insertion reactions of N-heterocycliccarbene (NHC) boranes and diazoesters can be catalyzed by NHC-boryl iodides and produce stable α-NHC-boryl esters. The conditions of the reaction resemble the previous rhodium-catalyzed transformations (only the catalyst is different); however, the mechanisms of the two reactions are probably very different. The new boryl iodide catalyzed method is adept
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