作者:Patrick Loos、Cyril Ronco、Matthias Riedrich、Hans-Dieter Arndt
DOI:10.1002/ejoc.201300160
日期:2013.6
Intramolecular aza-Wittig ring closures were applied to synthesize thiazolines, oxazolines, and imidazolines from β-azido thioester, ester, and amide precursors. The cyclization precursors were obtained from amino acid derivatives. Optimized conditions for diazo transfer with a fast rate and racemization suppression, (thio)esterification, and amide coupling reactions are described. The ring closure reaction can
分子内 aza-Wittig 环闭合用于从 β-叠氮基硫酯、酯和酰胺前体合成噻唑啉、恶唑啉和咪唑啉。环化前体是从氨基酸衍生物中获得的。描述了具有快速和外消旋化抑制、(硫代)酯化和酰胺偶联反应的重氮转移的优化条件。闭环反应可以在中性条件下用 PPh3 进行,并且发现对五元环具有高度的化学选择性。如果酰胺基团被甲苯磺酰基激活,则亚氨基膦的分子内闭环会提供具有位置特异性甲苯磺酰基保护的对映纯咪唑啉产品。