1,3-Dipolar cycloaddition of nitrones with 1,1-difluoroolefins gives rise to fluorinated isoxazolidines in 85% yield; subsequent Raney nickel reduction of the cycloadducts produces beta-lactams.
Regioselective synthesis of some isoxazolines and isoxazolidines bearing caprolactam moiety
作者:Akın Sağirli、Yaşar Dürüst
DOI:10.1080/00397911.2018.1448934
日期:2018.6.18
room temperature and the best protocol have been found for the transformation of nitrones to N-methyl isoxazolidines is silver acetate in refluxing xylene. The structural identification of target compounds was established by IR, nuclear magnetic resonance (NMR), high resolution mass spectrometry (HRMS) spectra, and X-ray diffraction analyses. GRAPHICAL ABSTRACT
摘要异恶唑啉和异恶唑烷系列是通过芳香醛酮和腈氧化物与 N-乙烯基己内酰胺通过区域选择性 1,3-偶极环加成反应获得的,仅以中等产率产生 5-己内酰胺取代的区域异构体。使用不同条件优化环加成反应。用于将腈氧化物转化为异恶唑的一种是室温下的三乙胺,并且已发现将硝酮转化为 N-甲基异恶唑的最佳方案是回流二甲苯中的乙酸银。目标化合物的结构鉴定是通过红外、核磁共振 (NMR)、高分辨率质谱 (HRMS) 光谱和 X 射线衍射分析建立的。图形概要
α,β-Unsaturated Fischer Carbene Complexes vs. 1,3-Dipoles: Reactions with Nitrones and Nitrilimines
作者:José Barluenga、Félix Fernández-Marí、Rosario González、Enrique Aguilar、Gustavo A. Revelli、Argimiro L. Viado、Francisco J. Fañanás、Bernardo Olano
The reaction of tert-butylalkynyl chromium Fischercarbenecomplex 1 with nitrones 2 affords β-enamino-ketoaldehydes 4 by the light-promoted rearrangement of the corresponding [3+2] cycloadduct carbenecomplexes3. On the other hand, [3+2] cycloaddition of chiral nonracemic Fischeralkenylcarbenecomplexes 19 with nitrilimines 10 yields enantiomerically pure Δ2-pyrazolines with high regio- and diastereoselectivity
The stereoselective synthesis of novel spiro-oxazinanone nucleosides 9 and 10 has been achieved by microwave assisted 1,3-dipolar cycloaddition of exo-glucal (1) and nitrones (2), and followed by reduction, stereospecific recyclization, and catalytic deprotection. The structures of the spironucleosides were determined according to the H-1 NMR, C-13 NMR, 2D NMR, MS, and X-ray analyses, and the biological activities of the title compounds against glycosidases (alpha-amylase, alpha-glucosidase, and beta-glucosidase) and cytotoxicity were also evaluated. (C) 2008 Elsevier Ltd. All rights reserved.
Hassan, Azfar; Wazeer, Mohammed I. M.; Ali, Sk. Asrof, Journal of the Chemical Society. Perkin Transactions 2 (2001), 1998, # 2, p. 393 - 399
作者:Hassan, Azfar、Wazeer, Mohammed I. M.、Ali, Sk. Asrof