Gold‐Catalyzed Bicyclic and [3+2]‐Annulations of Internal Propargyl Alcohols with Nitrones and Imines To Yield to Two Distinct Heterocycles
作者:Sayaji Arjun More、Tzu‐Hsuan Chao、Mu‐Jeng Cheng、Rai‐Shung Liu
DOI:10.1002/adsc.202001119
日期:2021.1.19
4‐a]indoles from 1‐oxo‐3‐yn‐4‐ols and nitrones is described; this new bicyclic annulation presents the first examples that internal alkynes can react with nitrones to undergo an oxoarylation route. DFT calculations indicate a [3,3]‐sigmatropic shift of initial alkenylgold intermediates to elude the intermediacy of gold carbenes. We also developed new [3+2]‐annulations of the same 1‐oxo‐3‐yn‐4‐ols with imines
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。
Rh<sub>2</sub>(<i>R</i>-TPCP)<sub>4</sub>-Catalyzed Enantioselective [3+2]-Cycloaddition between Nitrones and Vinyldiazoacetates
作者:Changming Qin、Huw M. L. Davies
DOI:10.1021/ja4069003
日期:2013.10.2
Rhodium-catalyzed reaction of vinyldiazoacetates with nitrones results in a formal [3+2]-cycloaddition to generate 2,5-dihydroisoxazoles with high levels of asymmetricinduction. The cascade reaction begins with a vinylogous addition event, followed by an iminium addition ring-closure/hydride migration/alkene isomerization cascade. Dirhodium tetrakis(triarylcyclopropanecarboxylates) are the optimum
Trimethylsilylketene smoothly reacts with α,N-diarylnitrones to give oxindoles in good yields. On the other hand, the reaction of trimethylsilylketene with N-arylmethylnitrones gives a mixture of N,N-diacylamines and N-acylamines.
Hetero-cope-umlagerungen -II. Einfache und flexible synthesen für 2-substituierte indole
作者:Siegfried Blechert
DOI:10.1016/s0040-4039(01)90006-1
日期:1984.1
The reaction of N-phenylhydroxylamine derivatives with electron withdrawing allenes gives o-alkylated anilines, which can further react to form 1,2-disubstituted indoles. 2-Substituted indoles are directly obtainable from reaction with N-phenyl-nitrones.
Iridium-Catalyzed Redox-Neutral C2 and C3 Dual C–H Functionalization of Indoles with Nitrones toward 7<i>H</i>-Indolo[2,3-<i>c</i>]quinolines
作者:Miao Li、Yaqun Dong、Cong Zhou、Junxue Bai、Jiang Cheng、Jianwei Sun、Song Sun
DOI:10.1021/acs.orglett.1c02975
日期:2021.11.5
An iridium-catalyzed redox-neutral C-2 and C-3 dualC–Hfunctionalization of indoles with nitrones has been developed, furnishing a range of 7H-indolo[2,3-c]quinolines with high efficiency and regioselectivity under mild reaction conditions. Notably, sequential multiple C–H bond cleavage and C–C bond formation constitute the key events of this process, in which nitrone serves as a building block and
已开发出铱催化氧化还原中性 C-2 和 C-3 双 C-H 官能化吲哚与硝酮,提供一系列 7 H-吲哚[2,3- c ]喹啉,在温和的条件下具有高效率和区域选择性反应条件。值得注意的是,连续的多重 C-H 键断裂和 C-C 键形成构成了该过程的关键事件,其中硝酮作为构建块和氧化剂。与之前的 7 H-吲哚并[2,3- c ]喹啉方法不同,这种新开发的反应具有容易获得的底物、操作简单、范围广、效率高到高和优异的区域选择性。