A new synthesis of β-phenylaminothioesters and β-lactams base-induced ring-opening of 2-phenyl-3-aryl-5-phenyl-thioisoxazolidines
作者:Leonardo Di Nunno、Antonio Scilimati
DOI:10.1016/s0040-4020(01)80250-7
日期:1993.1
Treatment of 2-phneyl-3-aryl-5-phenylthioisoxazolidines with alkyllithiums (n-BuLi, t-BuLi) at −78°C in THF gives β-phenylaminothioesters and/or the corresponding β-lactams in good yields. Complete conversion of β-aminothioesters into β-lactams can in any case be accomplished by treating them with CH3MgI/Et2O at 0° C. Isoxazolidine ring fragmentation to phenyl thioacetate and an imine is instead observed
苯基乙烯基硫醚与芳基N-苯基,N-甲基或N-叔丁基硝基的1,3-偶极环加成反应得到2-苯基(或2-甲基或2-叔丁基)-3-芳基-5-苯基硫代异恶唑烷根据已经公知的将不高度缺乏电子的双极性亲和剂环加成到硝酮上的区域选择性。在-78°C下于THF中用烷基锂(n -BuLi ,t -BuLi)处理2-苯甲基-3-芳基-5-苯基硫代异恶唑烷,得到高收率的β-苯基氨基硫代酯和/或相应的β-内酰胺。在任何情况下,都可以通过用CH 3 MgI / Et 2处理将β-氨基硫酯完全转化为β-内酰胺相反,通过在室温下或在N-烷基异恶唑烷的情况下进行反应,观察到异恶唑烷环断裂成硫代乙酸苯酯和亚胺是主要途径或排他性途径。