Synthesis of Indoles by Reductive Cyclization of Nitro Compounds Using Formate Esters as CO Surrogates
作者:Manar Ahmed Fouad、Francesco Ferretti、Dario Formenti、Fabio Milani、Fabio Ragaini
DOI:10.1002/ejoc.202100789
日期:2021.9.14
A very efficient, general and scalable protocol for the preparation of indoles and other N-heterocycles from suitably substituted nitroarenes using alkyl and phenyl formates as CO surrogates was described. Using phenyl formate, the products were isolated in yields often higher than those previously achieved by using gaseous CO. The mechanism of both the decarbonylation reaction of phenyl formate and
描述了使用烷基和苯基甲酸酯作为 CO 替代物从适当取代的硝基芳烃制备吲哚和其他N-杂环的非常有效、通用和可扩展的方案。使用甲酸苯酯,产物的分离产率通常高于以前使用气态 CO 实现的产率。通过动力学和机理研究阐明了甲酸苯酯的脱羰反应和环化反应的机理。
GaCl<sub>3</sub>-Catalyzed C–H Cyanation of Indoles with <i>N</i>-Cyanosuccinimide
作者:Xue Wang、Mohamed Makha、Shu-Wei Chen、Huaiji Zheng、Yuehui Li
DOI:10.1021/acs.joc.9b00416
日期:2019.5.17
An efficient GaCl3-catalyzed direct cyanation of indoles and pyrroles using bench-stable electrophilic cyanating agent N-cyanosuccinimide was achieved and afforded 3-cyanoindoles and 2-cyanopyrroles in good yields and excellent regioselectivities. Notably, this protocol exhibited high reactivity for unprotected indoles and was applicable to a broad range of indole and pyrrole substrates.
A series of alkyl and aryl formate esters were evaluated as CO sources in the Pd‐ and Pd/Ru‐catalyzed reductivecyclization of substituted nitro compounds to afford heterocycles, especially indoles. Phenyl formate was found to be the most effective, and it allowed the desired products to be obtained in excellent yields, often higher than those previously reported with pressurized CO. Through detailed
Synthesis of 3-Cyano-1<i>H</i>-indoles and Their 2′-Deoxyribonucleoside Derivatives through One-Pot Cascade Reactions
作者:Bin Li、Beibei Zhang、Xinying Zhang、Xuesen Fan
DOI:10.1021/acs.joc.6b01612
日期:2016.10.21
An efficient and economical synthetic approach toward 3-cyano-1H-indoles through the reactions of 2-(2-bromophenyl)acetonitriles with aldehydes and aqueous ammonia is presented. Mechanically, this novel protocol involves a one-pot cascade procedure consisting of an aldol-type condensation, a copper-catalyzed amination by using aqueous ammonia as a cheap and safe nitrogen source, and an intramolecular
Selective Access to 3-Cyano-1<i>H</i>-indoles, 9<i>H</i>-Pyrimido[4,5-<i>b</i>]indoles, or 9<i>H</i>-Pyrido[2,3-<i>b</i>]indoles through Copper-Catalyzed One-Pot Multicomponent Cascade Reactions
作者:Bin Li、Shenghai Guo、Ju Zhang、Xinying Zhang、Xuesen Fan
DOI:10.1021/acs.joc.5b00239
日期:2015.6.5
Novel and selective synthetic approaches toward indole derivatives via copper-catalyzedone-pot multicomponent cascade reactions of 1-bromo-2-(2,2-dibromovinyl)benzenes with aldehydes and aqueous ammonia are presented. Intriguingly, the concentration of ammonia, the molar ratio of reagents, and the structural features of the aldehyde substrate serve as key factors in controlling the selective formation