compounds containing one to four nitrogen atoms react with chlorodifluoromethane in the presence of concentrated aqueous sodium hydroxide and a catalyst, benzyltriethylammonium chloride (TEBAC) in dichloromethane or THF (phase-transfer catalysis, PTC) with formation of N-difluoromethyl substituted derivatives. The process takes place by reaction of N-anions from these heterocycles with difluorocarbene and
Synthesis of<i>gem</i>-Difluorocyclopropa(e)nes and O<i>-</i>, S<i>-</i>, N<i>-</i>, and P-Difluoromethylated Compounds with TMSCF<sub>2</sub>Br
作者:Lingchun Li、Fei Wang、Chuanfa Ni、Jinbo Hu
DOI:10.1002/anie.201306703
日期:2013.11.18
Two-in-one: Me3 SiCF2 Br is an efficient difluorocarbene source and is compatible with both neutral and aqueous basic conditions. Bromide-ion-initiated [2+1] cycloaddition with alkenes/alkynes and hydroxide ion promoted α-addition with (thio)phenols, (thio)alcohols, sulfinates, heterocyclic amines, and H-phosphine oxides give the corresponding gem-difluorinated compounds with broad functional-group tolerance.
<i>N</i>-Tosyl-<i>S</i>-difluoromethyl-<i>S</i>-phenylsulfoximine: A New Difluoromethylation Reagent for S-, N-, and C-Nucleophiles
作者:Wei Zhang、Fei Wang、Jinbo Hu
DOI:10.1021/ol900567c
日期:2009.5.21
The first alpha-difluoromethyl sulfoximine compound, 2, was successfully prepared by using the copper(II)-catalyzed nitrene transfer reaction. Compound 2 was found to be a novel and efficient difluoromethylation reagent for transferring the CF2H group to S-, N-, and C-nucleophiles. Deuterium-labeling experiments suggest that a difluorocarbene mechanism is involved in the current difluoromethylation reactions.
N -Difluoromethylation of imidazoles and pyrazoles using BrCF 2 PO(OEt) 2 under mild condition
作者:Ting Mao、Liang Zhao、Yang Huang、Yue-Guang Lou、Qiuli Yao、Xiao-Fei Li、Chun-Yang He
DOI:10.1016/j.tetlet.2018.06.003
日期:2018.7
A simple and efficient protocol for the direct N-difluoromethylation of imidazoles and pyrazoles has been developed. The reaction makes use of commercially available, non-ozone-depleting and easy handling BrCF2PO(OEt)2 as difluorocarbene precursor, and provides a cost-efficient and environmentally benign access to some difluoromethylated biologically relevant molecules.