The novel preparation of imidazol-2-ones in four steps from quinolines via an oxidative ring rearrangement is reported. (C) 2000 Elsevier Science Ltd. All rights reserved.
New protocols for the synthesis of 3,4-annulated and 4-substituted quinolines from β-bromo-α,β-unsaturated aldehydes and 1-bromo-2-nitrobenzene or 2-bromoacetanilide
摘要:
The palladium[0]-mediated Ullmann cross-coupling of readily available beta-bromo-alpha,beta-unsaturated aldehydes of the general form 2 with 1-bromo-2-nitrobenzene (3, X = Br) delivers products, 4, that undergo reductive cyclization to novel quinolines (5) upon exposure to indium in aqueous ammonium chloride or to Raney-nickel in the presence of dihydrogen. Analogous cross-coupling of 2-bromoacetanilide (6) with 2 affords products of type 7 that undergo in situ and K2CO3-mediated cyclization to give the same types of quinolines (5). (C) 2007 Elsevier Ltd. All rights reserved.
Direct C−H Arylation of Electron-Deficient Heterocycles with Arylboronic Acids
作者:Ian B. Seiple、Shun Su、Rodrigo A. Rodriguez、Ryan Gianatassio、Yuta Fujiwara、Adam L. Sobel、Phil S. Baran
DOI:10.1021/ja1066459
日期:2010.9.29
A directarylation of a variety of electron-deficientheterocycles with arylboronic acids has been developed. This new reaction proceeds readily at room temperature using inexpensive reagents: catalytic silver(I) nitrate in the presence of persulfate co-oxidant. The scope with respect to heterocycle and boronic acid coupling partner is broad, and sensitive functional groups are tolerated. This method
The arylation of C–H bonds to generate heteroaryl–aryl (Het–Ar) and arylated quinone (Quin–Ar) compounds has received great attention to achieve sustainable goals in synthetic chemistry. Despite significant advances, arylation of a broad range of Het–Ar and Quin–Ar derivatives remains a challenging task. Herein, a variety of heterocycles are arylated by using arylboronic acids in the presence of catalytic
aerobic oxidative dehydrogenation of N-heterocycles were examined in detail. Many tetrahydroquinoline derivatives and a broad range of other N-heterocycles could be tolerated by the catalytic system using a biomass-derived solvent as a reaction medium. Newly generated mixed crystal phases, noticeably enhanced surface areas and labile lattice oxygen of the OMS-2-based nanocomposite catalysts might contribute
Time-Resolved EPR Revealed the Formation, Structure, and Reactivity of N<i>-</i>Centered Radicals in an Electrochemical C(sp<sup>3</sup>)–H Arylation Reaction
作者:Yichang Liu、Biyin Shi、Zhao Liu、Renfei Gao、Cunlong Huang、Hesham Alhumade、Shengchun Wang、Xiaotian Qi、Aiwen Lei
DOI:10.1021/jacs.1c09341
日期:2021.12.15
over the past few years, while a vast majority of the reactions proceed through a radical pathway. Understanding the properties of radical intermediates is crucial in the mechanistic study of electrochemical transformations and will be beneficial for developing new reactions. Nevertheless, it is rather difficult to determine the “live” radical intermediates due to their high reactivity. In this work
A manganese-catalyzed cross-coupling reaction of heterocyclic chlorides with aryl- as well as alkylmagnesium halides has been developed. The reaction provides a variety of heterocyclic compounds under mild and practical reaction conditions using low amounts of manganese chloride as catalyst.