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。
Visible light promoted tandem dehydrogenation-deaminative cyclocondensation under aerobic conditions for the synthesis of 2-aryl benzimidazoles/quinoxalines from <i>ortho</i>-phenylenediamines and arylmethyl/ethyl amines
作者:Firdoos Ahmad Sofi、Rohit Sharma、Ravi Rawat、Asit K. Chakraborti、Prasad V. Bharatam
DOI:10.1039/d0nj03002c
日期:——
Visible light promoted dominosynthesis of 2-aryl benzimidazoles is reported through the reaction of ortho-phenylenediamines and arylmethyl amines underaerobicconditions. The methodology has wide substrate scope and tolerates a wide range of functional groups affording the products in high yields. The use of arylethyl amines instead of arylmethyl amines gives 2-aryl quinoxalines.
The iron-catalyzed heterocyclizations from 2-nitroanilines and benzylic alcohols to form benzimidazoles using hydrogen transfer reaction were investigated in this study. In the presence of dppf in toluene at 150 °C, various benzimidazoles were obtained in moderate to good yields within 24 h. The reaction was proposed to proceed via a cascade of alcohol oxidation, nitro reduction, condensation, and
Solvent-dependent metal-free chemoselective synthesis of benzimidazoles and 1,3,5-triarylbenzenes from 2-amino anilines and aryl alkyl ketones catalyzed by I2
作者:Yuxin Ding、Renchao Ma、Yongmin Ma
DOI:10.1016/j.tetlet.2021.153016
日期:2021.4
the synthesis of benzimidazoles and 1,3,5-triarylbenzenes via the annulation of 2-amino anilines and arylalkylketones or the cyclization of arylalkylketones, respectively. With 1,4-dioxane as the solvent, sequential CN bond formation followed by C(CO)-C(CH3) bond cleavage leads to the formation of benzimidazoles in a highly selective manner while aldol-type self-condensation of arylalkyl ketones
efficient and convenient Ni-catalyzed C–N bond formation for the synthesis of various benzimidazoles from various 2-haloanilines, aldehydes, and ammonia in a concise manner is reported. This protocol uses commercially available, nonhazardous, clean ammonia as a reaction partner instead of other nitrogen sources. Benzimidazoles, as the sole products, were obtained in high to excellent yields (up to 95%)
报道了一种高效且方便的 Ni 催化 C-N 键形成,用于以简洁的方式从各种 2-卤代苯胺、醛和氨合成各种苯并咪唑。该协议使用市售的、无害的、清洁的氨作为反应伙伴,而不是其他氮源。苯并咪唑作为唯一的产品,以高到极好的收率(高达 95%)获得。