title: Ruthenium-Catalyzed meta-Selective C-H Mono- and Difluoromethylation of Arenes through ortho-Metalation Strategy.
abstract: The first example for the ruthenium-catalyzed ligand-directed meta-selective C-H mono- and difluoromethylation is developed, affording a variety of new meta-mono- and difluoromethylated 2-phenylpyridines, 2-phenylpyrimidines, and 1-phenylpyrazoles in moderate-to-good yields. This new transformation exhibits broad substrate scope, good functional group tolerance, and high efficiency, and offers a practical approach to synthesize mono- and difluoromethylated arenes. Mechanistic studies indicate that a reaction pathway involving palladium-initiated radical species is involved in the catalytic cycle. The new dual catalytic system consisting of compatible ruthenium(II) and palladium(0) complexes enables the key processes of C-H activation and mono-/difluoromethyl-radical formation to occur and achieves the meta-selective functionalization efficiently. In addition, the present protocol can also be extended to non-fluoromethylation.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
authors.forename: Zhong-Yuan
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
authors.forename: Qi-Li
authors.initials: QL
authors.lastname: Li
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
authors.forename: Kun
authors.initials: K
authors.lastname: Jing
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
authors.forename: Guan-Wu
authors.identifier: http://orcid.org/0000-0001-9287-532X
authors.initials: GW
authors.lastname: Wang
keywords: fluoromethyl radical; fluoromethylation; meta-C−H activation; palladium catalysis; ruthenium catalysis