Visible-Light-Initiated Manganese Catalysis for C−H Alkylation of Heteroarenes: Applications and Mechanistic Studies
作者:Philippe Nuhant、Martins S. Oderinde、Julien Genovino、Antoine Juneau、Yohann Gagné、Christophe Allais、Gary M. Chinigo、Chulho Choi、Neal W. Sach、Louise Bernier、Yvette M. Fobian、Mark W. Bundesmann、Bhagyashree Khunte、Mathieu Frenette、Olugbeminiyi O. Fadeyi
DOI:10.1002/anie.201707958
日期:2017.11.27
A visible‐light‐driven Minisci protocol that employs an inexpensive earth‐abundant metal catalyst, decacarbonyldimanganese Mn2(CO)10, to generate alkyl radicals fromalkyliodides has been developed. This Minisci protocol is compatible with a wide array of sensitive functional groups, including oxetanes, sugar moieties, azetidines, tert‐butyl carbamates (Boc‐group), cyclobutanes, and spirocycles. The
nucleophilic carbon-centered radicals is furtheron developed by the following new achievements: i) utilization of the redoc system in several solvents; ii) utilization of benzoyl peroxide in alcohols; iii) carbamoylation by HCONH2 and H2O2 in the presence of catalytic amounts of Fe(II). These systems allow to obtain either substitution till now tried without success or reactions of industrial interest.
下列新成果进一步发展了质子化杂芳族碱基被亲核碳中心自由基直接取代的综合兴趣:ii)酒精中过氧化苯甲酰的利用;iii)在催化量的Fe(II)存在下通过HCONH 2和H 2 O 2进行氨基甲酰基化。这些系统允许获得直到现在为止一直没有成功的替代方案,或者获得工业利益的反应。极性效应在确定反应性,选择性和合成应用方面起主要作用;特别强调了吡啶基类型的强亲核中间基团在重新麦芽糖化步骤中的作用。
Redox-chain decomposition of hydroxylamine-O-sulphonic acid. A novel general source of nucleophilic radicals for the functionalization of heteroaromatic bases
Protonated heteroaromaticbases react with formamide, N,N-dimethylformamide, cyclic ethers, and methanol in the presence of hydroxylamine-O-sulphonicacid and catalytic amounts of an iron(II) salt to afford selective substitution by a redox chain process.
General electrochemical Minisci alkylation of <i>N</i>-heteroarenes with alkyl halides
作者:Roberto del Río-Rodríguez、Lorena Fragoso-Jarillo、Alberto F. Garrido-Castro、M. Carmen Maestro、Jose A. Fernández-Salas、José Alemán
DOI:10.1039/d2sc01799g
日期:——
Herein, we report, a general, facile and environmentally friendly Minisci-type alkylation of N-heteroarenes under simple and straightforward electrochemical conditions using widely available alkylhalides as radical precursors. Primary, secondary and tertiary alkyl radicals have been shown to be efficiently generated and coupled with a large variety of N-heteroarenes. The method presents a very high
Ligand-Accelerated Iron Photocatalysis Enabling Decarboxylative Alkylation of Heteroarenes
作者:Zhenlong Li、Xiaofei Wang、Siqi Xia、Jian Jin
DOI:10.1021/acs.orglett.9b01439
日期:2019.6.7
A mild, practical protocol for the decarboxylative alkylation of heteroarenes has been accomplished via iron photocatalysis. A diverse range of carboxylic acids readily undergo oxidative decarboxylation and then couple with a broad array of heteroarenes in this transformation. The photoexcited state lifetimes of iron complexes are typically much shorter than those of iridium and ruthenium complexes. Here we describe our effort on iron photocatalysis by utilizing the intramolecular charge transfer pathway of iron-carboxylate complexes.