Key Laboratory of Organofluorine Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China.
Bayer AG, Research & Development, Pharmaceuticals, 178 Müllerstraße, Berlin 13342, Germany.
J Org Chem. 2021 Feb 5;86(3):2854-2865. doi: 10.1021/acs.joc.0c02783. Epub 2021 Jan 19.
We describe, for the first time, two protocols for direct difluoromethylation of unactivated alkyl bromides and iodides. Reactions of alkyl iodides with TMSCFH were mediated by a copper catalyst using CsF as the activator, while reactions of less reactive alkyl bromides required a combination of palladium and a stoichiometric amount of CuI as the catalysts. Preliminary mechanistic studies of the synergistic Pd/Cu-catalyzed difluoromethylation of alkyl bromides suggest that it proceeds likely via a Pd(I)/Pd(III) catalytic cycle.
我们首次描述了两种直接二氟甲基化未活化的烷基溴化物和碘化物的方法。碘化烷基与 TMSCFH 的反应由铜催化剂介导，使用 CsF 作为活化剂，而反应性较低的溴化烷基则需要钯和化学计量的 CuI 作为催化剂的组合。协同 Pd/Cu 催化的溴代烷烃二氟甲基化的初步机理研究表明，其可能通过 Pd(I)/Pd(III)催化循环进行。
