Benzylic Aroylation of Toluenes Mediated by a LiN(SiMe<sub>3</sub>)<sub>2</sub>/Cs<sup>+</sup> System
作者:Yuanyun Gu、Zhen Zhang、Yan-En Wang、Ziteng Dai、Yaqi Yuan、Dan Xiong、Jie Li、Patrick J. Walsh、Jianyou Mao
DOI:10.1021/acs.joc.1c02446
日期:2022.1.7
Chemoselective deprotonative functionalization of benzylic C–H bonds is challenging, because the arene ring contains multiple aromatic C(sp2)–H bonds, which can be competitively deprotonated and lead to selectivity issues. Recently it was found that bimetallic [MN(SiMe3)2 M = Li, Na]/Cs+ combinations exhibit excellent benzylic selectivity. Herein, is reported the first deprotonative addition of toluenes
An expedient route to heterocycles through α-arylation of ketones and arylamides by microwave induced thermal S<sub>RN</sub>1 reactions
作者:Silvia M. Soria-Castro、Daniel A. Caminos、Alicia B. Peñéñory
DOI:10.1039/c4ra00120f
日期:——
irradiation promotes a quick aromatic nucleophilic substitution by a thermally induced electrontransferprocess to form new C–C bonds by the coupling of aryl radicals and enolate nucleophiles. Diverse 2-aryl-1-phenylethanones can be prepared by the direct α-arylation of acetophenone with different haloarenes. The ketone enolate anion is generated by deprotonation with tBuOK in DMSO and the reaction is carried
Acylpalladium species derivable via oxidative addition of a Pd phosphine complex with aryl and alkenyl iodides and CO insertion can react, either intramolecularly or tntermolecularly, with enolates generated in situ to give the corresponding enol esters and enol laotones.
Reactions of o-iodohalobenzenes with carbanions of aromatic ketones. Synthesis of 1-aryl-2-(o-halophenyl)ethanones
作者:María T. Baumgartner、Liliana B. Jiménez、Adriana B. Pierini、Roberto A. Rossi
DOI:10.1039/b201692c
日期:2002.5.22
retention of one halogen. The monosubstituted dehalogenated compounds are formed in low overall yields in the reactions of o-diiodobenzene with the carbanions of 1-(2-naphthyl)ethanone and of acetophenone and in the reaction of o-bromoiodobenzene with the carbanion of propiophenone. The reactions can be performed in the dark, with usually increased yields of substitution under irradiation, as well as under
Density functional theory (DFT) calculations reveal that the two adjacent iodines in o-diiodoarenes play critical roles in the formation of aryne. The nucleophilic attack of hydride to the electrophilic iodine requires that the adjacent iodine act as a directing group to accelerate this process, whereas mono-substituted iodobenzene lacking the neighboring-group participation makes it difficult. The in-situ-formed
在这里,我们记录了以“旧”邻二碘芳烃作为芳炔祖体的芳炔化学的重新发明。我们建立了 NaH 介导的活化策略,以受控方式生成高反应性芳炔物种。所得芳炔可以有效地参与与未活化酮的C-C σ键插入反应,这是现有方法难以实现的。密度泛函理论 (DFT) 计算表明o中的两个相邻碘-二碘芳烃在芳炔的形成中起关键作用。氢化物对亲电子碘的亲核攻击需要邻近的碘充当导向基团来加速这一过程,而缺乏邻近基团参与的单取代碘苯则使其变得困难。酮原位形成的烯醇化物被建议采用四聚体聚集体与芳烃反应,这解释了具有大取代基的底物的高区域化学性。