Metal-free construction of dihydropyrazino[2,3-<i>b</i>]indoles from 2-aminoacetophenones, isocyanates and 1,2-diamines
作者:Jingxi Fang、Jiayao Fang、Yingbo Rao、Huanyi Qiu、Zhentao Pan、Yongmin Ma
DOI:10.1039/d3ob01967e
日期:——
A Brønsted acid/iodine co-mediated approach to construct dihydropyrazino[2,3-b]indoles in 2-MeTHF as a green solvent at room temperature was established. A wide range of diversely substituted dihydropyrazino[2,3-b]indoles (42 examples, 61–85% yields) were synthesized under mild conditions, even on a gram scale. This protocol features organocatalysts, an eco-friendly solvent, mild conditions, readily
建立了在室温下以 2-MeTHF 作为绿色溶剂构建二氢吡嗪并[2,3- b ]吲哚的布朗斯台德酸/碘共介方法。在温和条件下合成了多种不同取代的二氢吡嗪并[2,3- b ]吲哚(42 个实例,产率 61-85%),甚至是克级的。该方案具有有机催化剂、环保溶剂、条件温和、底物易于获取、底物范围广泛和操作简单等特点。
Environmentally Benign Synthesis of Quinoline–Spiroquinazolinones by Iron-Catalyzed Dehydrogenative [4 + 2] Cycloaddition of Secondary/Tertiary Anilines and 4-Methylene-quinazolinones
作者:Yuxin Ding、Jinqiang Kuang、Xuqiong Xiao、Lei Wang、Yongmin Ma
DOI:10.1021/acs.joc.1c01602
日期:2021.9.3
We report an efficient iron-catalyzed cross-dehydrogenative coupling [4 + 2] annulation of secondary/tertiary anilines with quinazolinones to generate quinoline–spiroquinzolinones. The reaction proceeds smoothly with a relatively broad variety of functional groups, a cheap transition metal catalyst (FeCl3), and environmentally friendly oxidant (H2O2/O2) under mild reaction conditions. Creatively, N-methylanilines
我们报告了一种有效的铁催化交叉脱氢偶联 [4 + 2] 二级/三级苯胺与喹唑啉酮的环化,以生成喹啉-螺喹唑啉酮。在温和的反应条件下,该反应在相对广泛的官能团、廉价的过渡金属催化剂(FeCl 3)和环境友好的氧化剂(H 2 O 2 /O 2)下顺利进行。创造性地,N-甲基苯胺首次用于环加成,因为甲基和亚甲基源都连接到四氢喹啉的 N 原子上。
NHC-Stabilized Gold(I) Complexes: Suitable Catalysts for 6-<i>exo</i>-dig Heterocyclization of 1-(<i>o</i>-Ethynylaryl)ureas
作者:Ana Gimeno、Mercedes Medio-Simón、Carmen Ramírez de Arellano、Gregorio Asensio、Ana B. Cuenca
DOI:10.1021/ol100595s
日期:2010.5.7
3-substituted 1-(o-ethynylaryl)ureas 1 selectively undergo either 6-exo-dig or 5-endo-dig cyclization (to give 4-methylene-3,4-quinazolin-2-ones 2 or indoles 3, respectively) depending on the choice of the metal, ligand, and reaction conditions. The best results (up to 96% yield) in the preparation of the hydroamination products 2 are achieved with the highly bulky NHC-stabilized cationic gold(I) complex