Iodomethane as an organocatalyst for the aerobic ortho-selective trifluoromethylation of pyridines  

作　　者：Jianjin Yu Renqin Zhan Chao-Jun Li Huiying Zeng 

机构地区：[1]State Key Laboratory of Applied Organic Chemistry,College of Chemistry and Chemical Engineering,Lanzhou University.Lanzhou 730000,China [2]Department of Chemistry,FQRNT Centre for Green Chemistry and Catalysis,McGll University,Montreal,Ouebec H3A OB8,Canada

出　　处：《Science China Chemistry》2023年第1期133-138,共6页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(21971093);the Fundamental Research Funds for the Central Universities(lzujbky-2021-sp53);the International Joint Research Centre for Green Catalysis and Synthesis(2016B01017);the 111 Project。

摘　　要：Iodomethane is usually used as an electrophilic methylation reagent.Herein,we report its use as a C1 organocatalyst for the aerobic ortho-selective trifluoromethylation of pyridines in the absence of a transition metal.Trifluoroacetic acid(TFA)was employed as an inexpensive,readily available trifluoromethyl source.The reaction efficiently produced a variety of trifluoromethylation products,with good functional group compatibility.Pyridine-containing drug molecules could also be selectively trifluoromethylated for late-stage functionalizations.Mechanistic studies showed that iodomethane selectively reacted with the pyridine starting material,rather than the pyridine product,to generate the corresponding N-methylpyridinium iodide.The decarboxylation of trifluoroacetic acid produced a trifluoromethyl anion,which added to the methylpyridinium iodide,and the subsequent aerobic rearomatization led to the generation of the ortho-trifluoromethylated product.

关 键 词：iodomethane-catalysis TRIFLUOROMETHYLATION PYRIDINES transition-metal-free trifluoroacetic acid 

分 类 号：O643.36[理学—物理化学]