描述了一种由金催化的由1-氧代3-yn-4-醇和硝酮合成的1,3-二氢恶唑并[3,4- a ]吲哚的方法;这种新的双环环化反应是第一个实例,表明内部炔烃可以与硝酮反应进行羰基化反应。DFT计算表明,初始烯基金中间体发生了[3,3]-σ位移,从而避开了金卡宾的中间产物。我们还用亚胺开发了相同的1-oxo-3-yn-4醇与新的[3 + 2]环,有效地生成了oxazolidin-4-yylne衍生物。这些1-oxo-3-ynes的束缚醇可捕获其亚稳的2-azadienium中间体,从而实现新颖的环化反应。我们的机械分析表明,尽管两种产品在结构上相关,但它们是由两个独立的系统生产的。
(TGA) and diffuse reflection spectroscopy (DRS). The CdSnanorods have 12–18 nm sizes according to TEM. The catalyst was used successfully in the chemoselective photocatalytic reduction of nitroarenes using a CdS/poly ethyleneglycol 400–water system (CdS/PEG–H2O). The reaction was successfully carried out under green and blue LED illumination by using ammonium formate as a sacrificial electron donor in
Cooperative Silver- and Base-Catalyzed Diastereoselective Cycloaddition of Nitrones with Methylene Isocyanides: Access to 2-Imidazolinones
作者:Yan Chen、Yijing Wu、Andrey Shatskiy、Yuhe Kan、Markus D. Kärkäs、Jian-Quan Liu、Xiang-Shan Wang
DOI:10.1002/ejoc.202000437
日期:2020.6.23
A protocol involving cooperative silver‐ and base‐catalyzed diastereoselective cycloaddition of nitrones with isocyanides is described, delivering several valuable 2‐imidazolinones derivatives as single diastereomers. A plausible reaction mechanism is rationalized by DFT calculations. DBU plays dual roles in the developed reaction, acting as both the base and ligand.
Gold(I)-Catalyzed [4 + 2] Annulation between Arylynes and C,N-Diaryl Nitrones for Chemoselective Synthesis of Quinoline Scaffolds via Gold Acetylide Intermediates
作者:Debashis Barik、Rai-Shung Liu
DOI:10.1021/acs.joc.2c00274
日期:2022.6.3
Gold-catalyzed synthesis of quinoline derivatives via [4 + 2] annulation between terminal arylynes and nitrones is described. Our mechanistic analysis supports the participation of alkynylgold intermediates, instead of a typical gold–carbene species in recently reported gold catalysis. These nucleophilic alkynylgold species react with nitrones via Povarov-type reactions. Cheap, readily available materials
Gold‐Catalyzed Cyclizations and [3+2]‐Annulation Cascades between 1,5‐Diyn‐3‐ols and Nitrones to Construct Carbazole Frameworks
作者:Sudhakar Dattatray Tanpure、Manoj Dilip Dhole、Rai‐Shung Liu
DOI:10.1002/adsc.202300711
日期:2023.9.5
Gold-catalyzedcascade reactions between 1,5-diyn-3-ols and nitrones to deliver carbazole derivatives are described. Such cascade reactions are applicable to facile synthesis of polyaromatic compounds containing carbazole subunits. Notably, the reaction mechanism involves unexpected oxoarylations, rather than oxidative Mannich reactions as known for but-1-yn-4-ols. Our control experiments indicate