Applications and Limitations of the I<sub>2</sub>-Mediated Carbamate Annulation for the Synthesis of Piperidines: Five- versus Six-Membered Ring Formation
作者:Hilary M. Corkran、Stefan Munneke、Emma M. Dangerfield、Bridget L. Stocker、Mattie S. M. Timmer
DOI:10.1021/jo401512h
日期:2013.10.4
A protecting-group-free synthetic strategy for the synthesis of piperidines has been explored. Key in the synthesis is an I2-mediated carbamate annulation, which allows for the cyclization of hydroxy-substituted alkenylamines into piperidines, pyrrolidines, and furans. In this work, four chiral scaffolds were compared and contrasted, and it was observed that with both d-galactose and 2-deoxy-d-galactose
已经探索了用于合成哌啶的无保护基的合成策略。在合成关键是I 2介导的氨基甲酸酯环,其允许羟基取代alkenylamines的环化成哌啶,吡咯烷,和呋喃。在这项工作中,4个手性支架,比较和对比,并且据观察,与两个d半乳糖和2-脱氧d半乳糖作为原料,将变换到是哌啶-1- deoxygalactonorjirimycin(DGJ)和4-外延-可以通过几个步骤和良好的总收率分别获得fagomine。当d葡萄糖被用作起始材料,只有呋喃产物形成,而使用2-脱氧的d-葡萄糖导致化学和立体选择性的降低以及四种产物的形成。可以提供每种环糊精产物形成的机理解释,这有助于我们更好地理解哌啶合成中氨基甲酸酯环糊精的范围和局限性。