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.
Room temperature iron(<scp>ii</scp>)-catalyzed radical cyclization of unsaturated oximes with hypervalent iodine reagents
作者:Shichao Yang、Hongji Li、Pinhua Li、Jingya Yang、Lei Wang
DOI:10.1039/c9ob02424g
日期:——
Here, we disclose an iron(ii)-catalyzed I-O bond cleavage of Koser's hypervalent iodine reagents (HIRs) that initiated the radical cyclization of unsaturated oximes at room temperature. This strategy is successfully applied for the construction of the isoxazoline backbone in an efficient manner. In particular, the direct introduction of a TsO group into products facilitates their late-stage transformations
We report here a novel cleavage method for polystyrene-supported selenium resin using CH3I-NaI under mild conditions to prepare 3,5-disubstituted isoxazolines. The polymer selenium resins can be reused without further transformation.
Trichloroisocyanuric Acid Promoted Cascade Cyclization/Trifluoromethylation of Allylic Oximes: Synthesis of Trifluoromethylated Isoxazolines
作者:Weigang Zhang、Yingpeng Su、Ke-Hu Wang、Lili Wu、Bingbing Chang、Ya Shi、Danfeng Huang、Yulai Hu
DOI:10.1021/acs.orglett.6b03582
日期:2017.1.20
Cheap and commercially available trichloroisocyanuric acid has been used to promote trifluoromethylation by using TMSCF3 as the trifluoromethyl source. The method provides a novel and efficient protocol for the construction of CF3-containing 4,5-dihydroisoxazoles from allylic oximes in good to excellent yields.