Efficient synthesis of isoxazoles and isoxazolines from aldoximes using Magtrieve™ (CrO2)
作者:Sandeep Bhosale、Santosh Kurhade、Uppuleti Viplava Prasad、Venkata P. Palle、Debnath Bhuniya
DOI:10.1016/j.tetlet.2009.04.073
日期:2009.7
Treatment of aldoximes 1 with Magtrieve™ (CrO2) in presence of dipolarophile 3 or 4, furnished a variety of isoxazolines 5a–u and isoxazoles 6a–q as 1,3-dipolar cycloaddition (1,3-DC) products (38 examples; 63–90% isolated yields). In situ formation of a nitrile oxide intermediate was confirmed through isolation of the dimerization product furoxane 2a in absence of any dipolarophile. The methodology
在存在偶极亲和剂3或4的情况下,用Magtrieve ™(CrO 2)处理醛肟1,提供了各种异恶唑啉5a–u和异恶唑6a–q作为1,3-偶极环加成(1,3-DC)产品(38个例子) ; 63–90%的独立收益率)。通过在不存在任何双亲性物质的情况下分离二聚产物呋喃烷2a来确认一氧化氮中间体的原位形成。该方法已扩展到分子内一氧化氮环加成(INOC)反应,以获得高度有用的7-8色烷衍生物(分离产率为75-80%)。Magtrieve ™作为用于1,3-DC反应的新试剂,它具有出色的底物通用性,同时还表现出对敏感保护基和富电子官能团的耐受性。