A novel Rh(III)-catalyzed C–H bond amination with the simultaneous release of a formyl group at distal positions is realized employing anthranil as a new type of C–Hamination reagent. This chemistry provides an efficient protocol for the synthesis of 2-acyl diarylamines, which are important structural motifs in many bioactive compounds. This new type of C–Hamination reagent possesses the advantages
Palladium-catalyzed C–H activation/C–C cross-coupling reactions via electrochemistry
作者:Cong Ma、Chuan-Qi Zhao、Yi-Qian Li、Li-Pu Zhang、Xue-Tao Xu、Kun Zhang、Tian-Sheng Mei
DOI:10.1039/c7cc07429h
日期:——
Palladium-catalyzed C–H activation/C–C cross-couplingreactions have emerged as attractive tools for organic synthesis. Typically, these reactions require stoichiometric chemical oxidants and exogenous ligands to regenerate the palladium catalyst and promote reductive elimination respectively. However, there are significant disadvantages associated with the use of traditional stoichiometric oxidants
Nitration of N‐heteroaromatics: The first example of palladium‐catalyzed direct ortho‐nitration of aryl CH bonds is described. A range of azaarenes, such as 2‐arylquinoxalines, pyridines, pyrazoles, and O‐methyl oximes, were nitrated with excellent chemo‐ and regioselectivity (see scheme; DCE=1,2‐dichloroethane). Preliminary mechanistic investigations support a silver‐mediated radical mechanism involving
Palladium-Catalyzed Chelation-Assisted Aromatic C–H Nitration: Regiospecific Synthesis of Nitroarenes Free from the Effect of the Orientation Rules
作者:Wei Zhang、Shaojie Lou、Yunkui Liu、Zhenyuan Xu
DOI:10.1021/jo400594j
日期:2013.6.21
ortho-nitration of aryl C–H bond is described. A range of azaarenes such as 2-arylquinoxalines, pyridines, quinoline, and pyrazoles were nitrated with excellent chemo- and regioselectivity. Using the O-methyl oximyl group as a removable directing group, the regiospecific synthesis of a variety of o-nitro aryl ketones was achieved starting from aryl ketones via a three-step process involving the Pd-catalyzed
A palladium-catalyzed ortho-directed alkylation of O-methyl ketoximes that proceeds through a regioselective ring-opening reaction of epoxides has been demonstrated. This C(sp2)–H activation/alkylation protocol was carried out in pivalic acid/1,1,1,3,3,3-hexafluoro-2-propanol (PivOH/HFIP, 2:8) as the solvent and was applied to various O-methyl ketoximes that contain either electron-donating or electron-withdrawing