Ruthenium-Catalyzed<i>meta</i>-Selective C−H Mono- and Difluoromethylation of Arenes through<i>ortho</i>-Metalation Strategy
作者:Zhong-Yuan Li、Liang Li、Qi-Li Li、Kun Jing、Hui Xu、Guan-Wu Wang
DOI:10.1002/chem.201700354
日期:2017.3.8
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
We have developed an efficient Pd‐catalyzed directed C—H bromination protocol, in which dimethyl sulfoxide (DMSO) is employed as oxidant with hydrobromic acid aqueous solution (HBr(aq)) as bromide source. The DMSO/HBr(aq) system, which is novelly and efficiently utilized in transition‐metal catalyzed C—H activation, illustrates its practicability by the operational simplicity, inexpensive and readily
Copper-Mediated Chelation-Assisted <i>Ortho</i> Nitration of (Hetero)arenes
作者:Lin Zhang、Zhenhua Liu、Huiqin Li、Guichun Fang、Badru-Deen Barry、Tuemay Abadi Belay、Xihe Bi、Qun Liu
DOI:10.1021/ol2028288
日期:2011.12.16
A novel copper-mediated chelation-assisted ortho C–H nitration of (hetero)arenes has been developed for the first time, which used dioxygen as terminal oxidant and 1,2,3-TCP as solvent, leading to the synthesis of nitroaromatics with excellent regioselectivity and in good yields. Mechanistic investigations indicate a mechanism involving a four-centered transition state, with simultaneous cleavage of
Rhodium-Catalyzed CS and CN Functionalization of Arenes: Combination of CH Activation and Hypervalent Iodine Chemistry
作者:Fen Wang、Xinzhang Yu、Zisong Qi、Xingwei Li
DOI:10.1002/chem.201504179
日期:2016.1.11
Rhodium‐catalyzed sulfonylation, thioetherification, thiocyanation, and other heterofunctionalizations of arenes bearing a heterocyclic directing group have been realized. The reaction proceeds by initial RhIII‐catalyzed CH hyperiodination of arene at room temperature followed by uncatalyzed nucleophilic functionalization. A diaryliodonium salt is isolated as an intermediate, which represents umpolung
Direct Decarboxylative<i>Meta</i>-Selective Acylation of Arenes via an<i>Ortho</i>-Ruthenation Strategy
作者:Kun Jing、Zhong-Yuan Li、Guan-Wu Wang
DOI:10.1021/acscatal.8b03695
日期:2018.12.7
using Ru3(CO)12 as the catalyst and α-oxocarboxylic acids as the acylation source, featured broad substrate scope, good functional group tolerance, and high regioselectivity. Mechanistic studies demonstrated that a radical process and an 18e-octahedral ruthenium species were involved in this reaction. The present work provides a new strategy for the regioselective meta-acylation reactions and will