synthesis of a new class of dihydrofuran-fused tetracyclic compounds, possessing a 2-oxa-furano-steroidal framework, has been achieved by successive electrocyclic reactions of benzocyclobutene derivatives. It has been revealed that the stereoselectivity of a key intramolecular [4+2] cycloaddition reaction can be controlled by installation of a bulky silyl substituent onto the furan ring resulting in
通过
苯并环丁烯衍
生物的连续电环反应,已实现了具有 2-
氧杂-
呋喃-甾体骨架的新型二
氢呋喃稠合四环化合物的有效合成。研究表明,关键的分子内 [4+2] 环加成反应的立体选择性可以通过在
呋喃环上安装庞大的甲
硅烷基取代基来控制,从而形成外加合物,这与我们过去观察到的选择性相反相关研究。已经对合成化合物的
生物活性进行了初步检查,并表明它们具有作为抗流感药物的潜力。(© Wiley-
VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)