WestCHEM, School of Chemistry, Joseph Black Building, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK.
Org Biomol Chem. 2018 May 30;16(21):3970-3982. doi: 10.1039/c8ob00924d.
A novel method for the stereoselective construction of hexahydroazuleno[4,5-b]furans from simple precursors has been developed. The route involves the use of our recently developed Brønsted acid catalysed cyclisation reaction of acyclic ynenones to prepare fused 1-furanyl-2-alkenylcyclopropanes that undergo highly stereoselective thermal Cope rearrangement to produce fused tricyclic products. Substrates possessing an E-alkene undergo smooth Cope rearrangement at 40 °C, whereas the corresponding Z-isomers do not react at this temperature. Computational studies have been performed to explain the difference in behaviour of the E- and Z-isomers in the Cope rearrangement reaction. The hexahydroazuleno[4,5-b]furans produced by Cope rearrangement have potential as advanced intermediates for the synthesis of members of the guaianolide family of natural products.
一种从简单前体制备六氢薁并[4,5-b]呋喃的新型立体选择性方法已经开发出来。该路线涉及使用我们最近开发的 Brønsted 酸催化非环炔酮的环化反应来制备稠合的 1-呋喃基-2-烯基环丙烷，它们经历高度立体选择性的热 Cope 重排以产生稠合的三环产物。具有 E-烯烃的底物在 40°C 下进行顺利的 Cope 重排，而相应的 Z-异构体在该温度下不反应。已经进行了计算研究来解释 E-和 Z-异构体在 Cope 重排反应中的行为差异。通过 Cope 重排产生的六氢薁并[4,5-b]呋喃有可能作为天然产物愈创木烷族成员合成的高级中间体。
