1-Oxaspiro[4.4]nonan-6-ones. Synthetic Access via Oxonium Ion Technology, Optical Resolution, and Conversion into Enantiopure Spirocyclic α,β-Butenolides
作者:Leo A. Paquette、Dafydd R. Owen、Richard Todd Bibart、Christopher K. Seekamp、Alexandra L. Kahane、James C. Lanter、Miriam Alvarez Corral
DOI:10.1021/jo010026o
日期:2001.4.1
A general approach to the synthesis of enantiomerically pure spirocyclic alpha,beta-butenolides is presented where the fundamental framework is rapidly elaborated by acid- or bromonium ion-induced rearrangement of the carbinol derived by addition of 2-lithio-4,5-dihydrofuran to cyclobutanone. Subsequent resolution of the resulting ketones by either sulfoximine or mandelate acetal technology has been
提出了合成对映体纯的螺环α,β-丁烯内酯的一般方法,其中基本构架通过酸或溴离子诱导的甲醇的重排反应而迅速完善,该重排反应是通过向2-硫代-4,5-二氢呋喃中添加而得到的。环丁酮。通过硫代亚胺或扁桃酸缩醛技术对所得酮的后续拆分已得到有效应用。这些结构单元的可获得性又使得获得以17、35和38为代表的二氢呋喃的对映异构体以及诸如25和31的内酯以及目标标题化合物成为可能。早期中间体的互补还原提供了额外的优势,即可以按需获得α-和β-立体异构甲醇系列。