A novel two-step procedure for the preparation of diprotected anthranilic acid derivatives from ortho-bromoanilines is described.
本文描述了一种从邻溴苯胺制备二保护氨基苯甲酸衍生物的新型两步程序。
Hydroarylation of Arenes via Reductive Radical-Polar Crossover
作者:Autumn R. Flynn、Kelly A. McDaniel、Meredith E. Hughes、David B. Vogt、Nathan T. Jui
DOI:10.1021/jacs.0c03926
日期:2020.5.20
photocatalytic system for the dearomative hydroarylation of benzenederivatives has been developed. Using a combination of an organic photoredox catalyst and an amine reductant, this process operates through a reductive radical-polar crossover mechanism where aryl halide reduction triggers a regioselective radical cyclization event, followed by anion formation and quenching to produce a range of complex spirocyclic
Indole Synthesis by Controlled Carbolithiation of <i>o</i>-Aminostyrenes
作者:Albane Kessler、Claire M. Coleman、Patchanee Charoenying、Donal F. O'Shea
DOI:10.1021/jo048723e
日期:2004.11.1
An effective synthesis of the functionalized indole ring system has been developed from substituted o-aminostyrene starting material. Our methodology involves a novel cascade reaction sequence of alkyllithium addition to the styrene double bond and subsequent trapping of the intermediate organolithium with a suitable electrophile, followed by an in situ ring closure and dehydration to generate the indole ring. This new reaction sequence allows for the introduction of molecular diversity at all positions on the indole scaffold. The procedure was shown to be successful with a range of both C and N substituents on the o-aminostyrenes. The reaction sequence was tolerant to the reactivity range of alkyllithiums such as tert-, sec-, and n-butyllithium. The electrophiles used were DMF, which generated indole products with C-2 unsubstituted, and nitriles, which incorporated the nitrile substituent at C-2. The o-aminostyrene starting materials were generated by a Pd-catalyzed cross-coupling reaction of a vinyl boronic acid equivalent with the readily available substituted o-bromoanilines.
Organocatalyst in Direct C(<sub>sp</sub><sup>2</sup>)–H Arylation of Unactivated Arenes: [1-(2-Hydroxyethyl)-piperazine]-Catalyzed <i>Inter</i>-/<i>Intra</i>-molecular C–H Bond Activation
作者:Lalit Yadav、Mohit K. Tiwari、Bharti Rajesh Kumar Shyamlal、Sandeep Chaudhary
DOI:10.1021/acs.joc.0c01019
日期:2020.6.19
promotes both inter- and intra-molecular direct C(sp2)–H arylations of unactivated arenes in the presence of potassium tert-butoxide. While the inter-molecular C–H arylation of unactivated benzenes with aryl halides (Ar–X; X = I, Br, Cl) toward biaryl syntheses underwent smoothly in the presence of only 10 mol % organocatalyst, the intra-molecular C–H arylation catalytic system composed of 40 mol % each
本文介绍的1-(2-羟乙基) -哌嗪的标识为一个新的,高性价比的,高效率的有机催化剂,其促进两者间-和内-分子直接C(SP 2)在未活化的芳烃的芳基化-H叔丁醇钾的存在。当未活化的苯与芳基卤化物(Ar–X; X = I,Br,Cl)朝联芳基合成的分子间C–H芳基化在仅有10 mol%有机催化剂存在下顺利进行,而分子内C–H芳基化催化体系,分别由40摩尔%的催化剂和添加剂(4-二甲基氨基吡啶(DMAP))组成。新型催化剂还能够同时在一个锅中同时进行分子间和分子内直接芳基化。机理研究证实了芳基自由基阴离子的参与,并通过单电子转移(SET)机制进行。较大的底物范围,较高的官能团耐受性,竞争实验,克级合成和动力学研究进一步凸显了该方法的重要性和通用性以及新催化剂的相容性。据我们所知,这是关于任何有机催化剂的第一份报告,该报告以单一形式详细报告了未活化芳烃的分子间和分子内直接C(sp 2)-H芳基化反应。