Visible-Light Photoredox Catalyzed Double C–H Functionalization: Radical Cascade Cyclization of Ethers with Benzimidazole-Based Cyanamides
作者:Si Jiang、Xiao-Jing Tian、Shu-Yao Feng、Jiang-Sheng Li、Zhi-Wei Li、Cui-Hong Lu、Chao-Jun Li、Wei-Dong Liu
DOI:10.1021/acs.orglett.0c03853
日期:2021.2.5
simple ethers with cyanamides is developed at roomtemperature. This strategy involves sequential inert Csp3-H/Csp2-H functionalizations through intermolecular addition reaction of oxyalkyl radicals to N-cyano groups followed by radical cyclization of iminyl radicals in situ generated with C-2 aryl rings. This method allows for efficient synthesis of tetracyclic benzo[4,5]imidazo[1,2-c]quinazolines. Importantly
在室温下开发了一种简单的醚与氰胺的可见光光氧化还原催化的自由基级联环化反应。该策略涉及通过氧烷基自由基与N-氰基的分子间加成反应,随后通过C-2芳基环原位产生的亚氨基自由基的自由基环化,依次进行惰性C sp3- H / C sp2- H官能化。该方法可以有效合成四环苯并[4,5]咪唑并[1,2- c ]喹唑啉。重要的是,这是氰酰胺分子间-分子间自由基级联环化反应的第一个例子。
Diversity-oriented synthesis of imidazo[2,1-<i>a</i>]isoquinolines
作者:Shaoyu Mai、Yixin Luo、Xianyun Huang、Zhenghao Shu、Bingnan Li、Yu Lan、Qiuling Song
DOI:10.1039/c8cc05390a
日期:——
Herein, we report an efficient and practical strategy for the synthesis of five types of imidazo[2,1-a]isoquinolines via Cp*RhIII-catalyzed [4+2] annulation of 2-arylimidazoles and α-diazoketoesters, whose structural and substituted diversity at 5- or 6-position can be precisely controlled by the α-diazoketoester coupling partners. Compared with previous reports, in this study, we merged two attractive
本文中,我们报告了通过Cp * Rh III催化的2-芳基咪唑和α-重氮酮酸酯的[4 + 2]环合反应合成五种咪唑并[ 2,1- a ]异喹啉的有效而实用的策略。可以通过α-重氮酮酸酯偶合伙伴精确控制5位或6位取代的多样性。与以前的报告相比,在这项研究中,我们通过选择合适的酯基团(–COOEt,–COO tBu或–COOiPr)或廉价的添加剂(HOAc或KOAc)。此外,通过几种生物活性化合物的简明合成和代表性药物的后期修饰,证明了这些方法的合成功效。
Magnetic nanoparticle-supported DABCO tribromide: a versatile nanocatalyst for the synthesis of quinazolinones and benzimidazoles and protection/deprotection of hydroxyl groups
supported on magnetic Fe3O4 nanoparticles (MNPs-DABCO tribromide) as a novel heterogeneous tribromide type compound was found to be an efficient and reusable nanocatalyst for the one-pot synthesis of 2-arylquinazolin-4(3H)-ones and 2-aryl-1H-benzo[d]imidazoles through oxidative cyclization of aldehydes with 2-aminobenzamides and 1,2-phenylenediamine, respectively. Also, MNPs-DABCO tribromide catalyzed tr
发现一种新型的非均相三溴化物类型化合物,负载在磁性Fe 3 O 4纳米颗粒上的1,4-二氮杂双环[2.2.2]辛烷三溴化物(MNPs-DABCO三溴化物)是一种高效且可重复使用的纳米催化剂,可用于一锅法合成2通过分别用2-氨基苯甲酰胺和1,2-苯二胺对醛进行氧化环化反应,制得-芳基喹唑啉-4(3 H)-ones和2-芳基-1 H-苯并[ d ]咪唑。而且,MNPs-DABCO三溴化物通过在室温下改变溶剂介质,催化了多种醇和酚的三甲基甲硅烷基化/四氢吡喃基化和甲硅烷基化/脱吡喃基化。
Benzimidazoles from Aryl Alkyl Ketones and 2-Amino Anilines by an Iodine Catalyzed Oxidative C(CO)–C(alkyl) Bond Cleavage
Novel molecular iodine catalyzed cyclization reactions of 2-amino anilines with aryl alkyl ketones under oxidant and metal-free conditions are described. The reaction likely involves sequential C–N bond formation followed by C(CO)–C(alkyl) bondcleavage. Various 2-substituted benzimidazoles are obtained in moderate to good yields in a single step from readily available acetophenones, propiophenones
Copper(II)-Catalyzed Oxidative Coupling of Anilines, Methyl Arenes, and TMSN<sub>3</sub> via C(sp<sup>3</sup>/sp<sup>2</sup>)–H Functionalization and C–N Bond Formation
Copper(II)-catalyzed cross-coupling of anilines, methyl arenes, and TMSN3 in the presence of tert-butylhydroperoxide at moderate temperature produced 2-aryl benzimidazoles via a tandem C(sp3/sp2)–H functionalization and C–N bond formations. The selectivity and multiple C–H functionalization of the simple substrates are significant practical features.