Iron-Catalyzed Highly para-Selective Difluoromethylation of Arenes

Wei-Tai Fan¹, Yuting Li¹, Dongjie Wang, Shun-Jun Ji^{1 ,*}（纪顺俊）, and Yingsheng Zhao^1,2,*（赵应声）

¹ Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science Soochow University, Suzhou 215123, China

² School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China

J. Am. Chem. Soc. 2020, 142, 20524--20530

Direct functionalization of a C–H bond at either the meta or para position by only changing the catalyst system poses a significant challenge. We herein report the [Fe(TPP)Cl]-enabled, selective, C–H difluoromethylation of arenes using BrCF₂CO₂Et as the difluoromethylation source, which successfully altered the selectivity from the meta to the para position. A preliminary mechanistic study revealed the iron porphyrin complex not only activated the aromatic ring but also induced para selectivity due to the influence of ligand sterics.

链接：https://pubs.acs.org/doi/abs/10.1021/jacs.0c09545