Nuclear fluorination of 3,5-diarylisoxazoles with Selectfluor®
摘要:
C-4 Fluorination of a series of 3,5-diarylisoxazoles has been accomplished using the N-F reagent Selectfluor(R). With substrates containing neutral or activating substituents on the 5-phenyl ring, acetonitrile at room temperature or at reflux could be used as solvent. However, when deactivating substituents were present, a higher reaction temperature was required for which sulfolane was found to be a good solvent. At this higher temperature, a unique trifluorination of the isoxazole nucleus by an addition mechanism occurred as a side reaction. (C) 2004 Elsevier B.V. All rights reserved.
Rhodium-Catalyzed Cascade Annulative Coupling of 3,5-Diarylisoxazoles with Alkynes
作者:Teppei Noguchi、Yuji Nishii、Masahiro Miura
DOI:10.1055/s-0037-1610376
日期:2019.1
the sequential construction of isoquinoline and naphtho[1,8-bc]pyran frameworks connected by a biaryl linkage is achieved by a single operation. Most of the obtained polycyclic compounds exhibit visible fluorescence in both the solution and the solid state. The hexaphenylated isoquinoline-naphthopyran conjugate (R = Ph) as a representative product shows a green emission which can be turned off by making
作为《五十周年综合报告》的一部分发行-黄金周年纪念日 抽象的 在Cu(II)氧化剂存在下,铑催化的3,5-二芳基异恶唑与三当量炔烃的级联环氧化反应平稳进行,其中异喹啉和萘并[1,8- bc ]吡喃骨架的顺序结构相连联芳键的单键操作是通过一次操作即可实现的。大部分获得的多环化合物在溶液和固态下均显示可见的荧光。作为代表产物的六苯基化异喹啉-萘并吡喃共轭物(R = Ph)显示绿色发射,可通过用酸制备异喹啉鎓盐来关闭该发射。通过用碱处理也可逆地开启发射。 在Cu(II)氧化剂存在下,铑催化的3,5-二芳基异恶唑与三当量炔烃的级联环氧化反应平稳进行,其中异喹啉和萘并[1,8- bc ]吡喃骨架的顺序结构相连联芳键的单键操作是通过一次操作即可实现的。大部分获得的多环化合物在溶液和固态下均显示可见的荧光。作为代表产物的六苯基化异喹啉-萘并吡喃共轭物(R = Ph)显示绿色发射,可通过用酸制备异喹啉鎓盐
An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes
作者:Pankaj V. Khairnar、Tsai-Hui Lung、Yi-Jung Lin、Chi-Yi Wu、Srinivasa Rao Koppolu、Athukuri Edukondalu、Praneeth Karanam、Wenwei Lin
DOI:10.1021/acs.orglett.9b01395
日期:2019.6.7
α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further
Synthesis of Isoxazolines and Isoxazoles via Metal-Free Desulfitative Cyclization
作者:Qiu Sun、Ling He、Jiaxin Cheng、Ze Yang、Yuansheng Li、Yulan Xi
DOI:10.1055/s-0037-1609480
日期:2018.6
bonds/construction of C–O bonds/elimination of SO2/C–N bond formation is achieved in sequence in the reaction system. A novel, one-pot reaction for the synthesis of isoxazolines and isoxazoles is developed via a cascade process under metal-free conditions. The approach involves the formation of intramolecular C–N and C–O bonds and intermolecular C–C bonds from aromatic alkenes or alkynes and N-hydroxysulfonamides
One-pot regioselective synthesis of substituted pyrazoles and isoxazoles in PEG-400/water medium by Cu-free nano-Pd catalyzed sequential acyl Sonogashira coupling–intramolecular cyclization
Catalyst efficacy of in situ generated Pd-nanoparticles (PdNPs) in the regioselective one-pot synthesis of 3,5-di & 3,4,5-trisubstituted pyrazoles and 3,5-disubstituted isoxazoles in environmentally benign PEG-400/H2O medium, which involves the sequential (i) Cu-free acyl-Sonogashira coupling (ASC) and (ii) intramolecular ynone–amine cyclization under PTC conditions was described. The results of controlled
在环境友好的PEG-400 / H 2中原位生成的Pd-纳米颗粒(PdNPs)在区域选择性一锅合成3,5-di和3,4,5-三取代的吡唑和3,5-二取代的异恶唑的催化剂效力描述了一种O介质,它涉及(i)在PTC条件下无Cu的酰基-Sonogashira偶联(ASC)和(ii)分子内的ynone-amine环化。受控实验的结果支持两个连续的催化循环(ASC /环化)的操作,并通过一锅法通过与炔酮结合的钯实现互补/相反的区域选择性。而且,就地一锅法反应序列的第一个催化循环后回收的PdNPs已连续五次再次使用。此外,在进行上述研究之前,某些常见的Pd-N-杂环卡宾(Pd-NHC)配合物在水和有机物中催化相同的一锅两步反应顺序(无铜ASC /环化)的功效还优化了溶剂。还可以从水中的Pd-NHC上方原位生成PdNP,但由于它们的尺寸较大,因此无法重复使用。