An Asymmetric Tandem Conjugative Addition-Intramolecular Cyclisation Process to Provide Functionalised 3,6-Dihydropyrans and 4,5-Epoxytetrahydropyrans
作者:Silvia Catalán-Muñoz、Constanze A. Müller、Steven V. Ley
DOI:10.1002/ejoc.200901145
日期:2010.1
The synthesis of 3,6-dihydropyrans and 4,5-epoxytetrahydropyrans starting from enantiomerically pure β-hydroxy aldehyde (prepared by an organocatalytic aldol reaction) is described. The key step is a tandem sequence, which consists of a base-promoted conjugative addition to a vinyl onium salt, followed by either an intramolecular Wittig process to provide 3,6-dihydropyran derivatives or an intramolecular
描述了从对映异构纯 β-羟基醛(通过有机催化羟醛反应制备)开始合成 3,6-二氢吡喃和 4,5-环氧四氢吡喃。关键步骤是串联序列,它由碱基促进的共轭加成到乙烯基鎓盐组成,然后是分子内 Wittig 过程以提供 3,6-二氢吡喃衍生物或分子内环化/环氧化过程以提供 4,5 -环氧四氢吡喃支架。这种方法得到的产物是聚酮化合物天然产物中常见的亚结构。