Preparation of isoxazol(in)yl substituted selenides and their further deselenenylation reaction to synthesize 3,5-disubstituted isoxazoles
摘要:
We report a mild 1,3-dipolar cycloaddition protocol for the preparation of 3-aryl-5-phenylselenomethyl isoxazoles and isoxazolines regioselectively. The former was further reacted with LDA and electrophilic substrates followed by selenoxide syn-elimination to afford 3-aryl-5-E-substituted-ethenyl isoxazoles stereoselectively and the latter was subjected to a 'two-step' elimination to afford 3-aryl-5-methyl isoxazoles. (C) 2004 Elsevier Ltd. All rights reserved.
BF<sub>3</sub>·OEt<sub>2</sub>-mediated cyclization of β,γ-unsaturated oximes and hydrazones with <i>N</i>-(arylthio/arylseleno)succinimides: an efficient approach to synthesize isoxazoles or dihydropyrazoles
作者:Wei Yu、Shichao Yang、Pei-Long Wang、Pinhua Li、Hongji Li
DOI:10.1039/d0ob01388a
日期:——
A highly efficient BF3·OEt2-mediated cyclization of β,γ-unsaturatedoximes and tosylhydrazones with N-(arylthio/arylseleno)succinimides has been established for the construction of N-heterocycles in a one-step manner. This metal-free cyclization provides direct access to isoxazoles and dihydropyrazoles in good to excellent yields at room temperature. The mechanistic experiments support the formation
Iodine(<scp>iii</scp>)-mediated intramolecular sulfeno- and selenofunctionalization of β,γ-unsaturated tosyl hydrazones and oximes
作者:Jing-Miao Yu、Chun Cai
DOI:10.1039/c7ob02892j
日期:——
A cascade radical cyclization/sulfenylation or selenylation of β,γ-unsaturatedhydrazones and oximes was realized under mild conditions with phenyliodine(III) diacetate (PIDA) as the sole oxidant, leading to the construction of diversely functionalized heteroatom-containing pyrazoline and isoxazoline derivatives. This metal-free radical process is suggested to encompass a sequential C–N/O and C–S/Se
Ultrasound-Promoted Radical Synthesis of 5-Methylselanyl-4,5-dihydroisoxazoles
作者:Daniela R. Araujo、Yanka R. Lima、Angelita M. Barcellos、Márcio S. Silva、Raquel G. Jacob、Eder J. Lenardão、Luana Bagnoli、Claudio Santi、Gelson Perin
DOI:10.1002/ejoc.201901611
日期:2020.2.7
An ultrasound‐promoted method to synthesize 5‐methylselanyl‐4,5‐dihydroisoxazoles through the radical cyclization of unsaturated oximes with diaryl diselenides using Oxone® as an oxidant and ethanol as the solvent is described.
Synthesis of Isoxazolines by the Electrophilic Chalcogenation of β,γ-Unsaturated Oximes: Fishing Novel Anti-Inflammatory Agents
作者:Eric F. Lopes、Filipe Penteado、Samuel Thurow、Mikaela Pinz、Angelica S. Reis、Ethel A. Wilhelm、Cristiane Luchese、Thiago Barcellos、Bianca Dalberto、Diego Alves、Marcio S. da Silva、Eder J. Lenardão
DOI:10.1021/acs.joc.9b01754
日期:2019.10.4
prepare chalcogen-functionalized isoxazolines. The strategy involves the reaction of β,γ-unsaturated oximes with electrophilic selenium and tellurium species, affording 19 new selenium- and tellurium-containing isoxazolines in good yields after 1 h at room temperature. The method was efficiently extended to the synthesis of 5 new (bis)isoxazoline ditellurides. One of the prepared compounds, 3-phenyl-5
Electrochemical Tandem Cyclization of Unsaturated Oximes with Diselenides: A General Approach to Seleno Isoxazolines Derivatives with Quaternary Carbon Center
cyclization of unsaturated oximes with diselenides has been developed to provide a general access to seleno isoxazolines (35 examples). This novel protocol features mild reaction conditions (metal‐ and oxidant‐free), good functional group tolerance (including ester, sulfone, heterocycles), and promising scalability. Moreover, two plausible reaction pathways have been proposed based on the cyclic voltammetry