Dicumyl Peroxide as a Methylating Reagent in the Ni-Catalyzed Methylation of Ortho C–H Bonds in Aromatic Amides
作者:Teruhiko Kubo、Naoto Chatani
DOI:10.1021/acs.orglett.6b00658
日期:2016.4.1
The direct methylation of ortho C–H bonds in aromatic amides with dicumyl peroxide (DCP) using a nickel complex as the catalyst is reported. The reaction shows a high functional group tolerance and is inhibited by radical scavengers. In reactions of meta-substituted aromatic amides, the reaction proceeds in a highly selective manner at the less hindered C–H bonds.
Mixed Directing-Group Strategy: Oxidative C−H/C−H Bond Arylation of Unactivated Arenes by Cobalt Catalysis
作者:Cong Du、Peng-Xiang Li、Xinju Zhu、Jian-Feng Suo、Jun-Long Niu、Mao-Ping Song
DOI:10.1002/anie.201607719
日期:2016.10.17
and a concerted metalation–deprotonation process (pyridine‐directed), were involved to activate two different inert aromatic C−H bonds. Moreover, the aryl radicals have been trapped by 2,6‐di‐tert‐butyl‐4‐methylphenol to form benzylated products. This unique strategy should be useful in the design of other arene C−H/C−H cross‐couplings as well.
A mild and efficient protocol for the synthesis of 2,2′-difunctional biaryls from readily available benzamides and oximes by Co(OAc)2·4H2O catalysis has been developed. The catalytic cycle that includes aerobic oxidation of Co(I) to Co(III) is successfully achieved for the first time through dual-chelation-assisted C–H/C–H coupling with the assistance of catalytic Mn(acac)3. The catalytic system exhibits
C5-benzoxylation with benzoylperoxide produced a variety of potentially bioactive 8-arylcarboxamido-5-benzoyloxy quinoline derivatives. The efficiency of the reaction reflects from the wide substrate scope with electronic differentiation on carboxamide and acyl peroxide in addition to tolerance of halo substitutions on either of the aryls. The reaction is additive, silver free and proceeds without
Synthesis of Chiral Spirolactams via Sequential C−H Olefination/Asymmetric [4+1] Spirocyclization under a Simple Co
<sup>II</sup>
/Chiral Spiro Phosphoric Acid Binary System
作者:Wen‐Kui Yuan、Bing‐Feng Shi
DOI:10.1002/anie.202108853
日期:2021.10.18
An unprecedented enantioselective synthesis of spiro-γ-lactams via a sequential C−H olefination/asymmetric [4+1] spirocyclization under a simple CoII/chiral spiro phosphoric acid (SPA) binary system is reported. A range of biologically important spiro-γ-lactams are obtained with high levels of enantioselectivity (up to 98 % ee). The concise, asymmetric synthesis of an aldose reductase inhibitor was
报道了在简单的 Co II /手性螺磷酸 (SPA) 二元体系下,通过连续的 C-H 烯化/不对称 [4+1] 螺环化,对螺-γ-内酰胺进行了前所未有的对映选择性合成。以高水平的对映选择性(高达 98% ee)获得了一系列生物学上重要的螺-γ-内酰胺。成功实现了醛糖还原酶抑制剂的简洁、不对称合成。值得注意的是,与之前依赖使用环戊二烯基或其衍生物(非手性 Cp*、Cp tBu或手性 Cp x)连接的 Co III 的报告相反 需要繁琐步骤来制备的复合物,廉价且可商购的四水合乙酸钴 (II) 被用作有效的预催化剂。