Experimental Evidence on the Formation of Highly Strained 6,7‐Dihydroazeto[2,1‐
<i>b</i>
]oxazol‐3‐ium Derivatives as Reactive Intermediates
作者:Wenlai Xie、Simin Sun、Jiaxi Xu
DOI:10.1002/hlca.202100187
日期:2022.2
7-dihydroazeto[2,1-b]oxazol-3-ium derivatives, which can be generated in situ and further undergo elimination and nucleophilic displacement immediately due to their high strain. 6,7-Dihydroazeto[2,1-b]oxazol-3-ium species are unstable and cannot be isolated from the reaction mixtures. They also provide an efficient method for the synthesis of 2-vinyloxazole derivatives.
形成高度应变的 6,7-dihydroazeto[2,1- b ]oxazol-3-ium 衍生物 (4-oxa-1-azabicyclo[3.2.0]hepta-1(5),2-dien-1-ium ) 作为反应性中间体,通过用三氯氧化磷作为脱水剂处理N -2-aryl-2-oxoethylazetidin-2-ones,通过消除得到 2-乙烯基恶唑作为主要产物,2-(2-氯乙基)恶唑作为通过氯阴离子的亲核取代生成副产物。目前的结果为高应变 6,7-dihydroazeto[2,1 - b ]oxazol-3-ium 衍生物的形成和存在提供了重要和有用的信息,这些衍生物可以原位生成并且由于它们的高应变立即发生消除和亲核置换。6,7-Dihydroazeto[2,1 - b ]oxazol-3-ium 物质不稳定,不能从反应混合物中分离出来。它们还为合成 2-乙烯基恶唑衍生物提供了一种有效的方法。