Photoreactions of Tricyclic α-Cyclopropyl Ketones and Unsaturated Enones – Synthesis of Polyquinanes and Analogous Ring Systems
作者:Nikolay T. Tzvetkov、Beate Neumann、Hans-Georg Stammler、Jochen Mattay
DOI:10.1002/ejoc.200500546
日期:2006.1
Polycyclic systems of both angular and propellane type have been synthesized through intramolecular radical cyclization reactions, by photochemically induced electron transfer of tricyclic a-cyclopropyl ketones or by photolysis of unsaturated enones. In general, tricyclic a-cyclopropyl ketones, each bearing an alkynyl or alkenyl side chain at the position gamma to the carbonyl group, were used as starting
通过分子内自由基环化反应、三环α-环丙基酮的光化学诱导电子转移或不饱和烯酮的光解,已合成角型和推进烷型多环系统。通常,使用三环α-环丙基酮作为起始材料,每个酮在羰基的γ位置带有炔基或烯基侧链。该反应导致一个环丙基键的区域选择性裂解,并通过串联断裂 - 自由基/自由基阴离子反应途径形成三到四环系统。环化(外/内)的区域选择性取决于不饱和侧链的长度。在涉及具有烷氧基甲基侧链的 α-环丙烷衍生物的情况下,观察到了各种非环化过程。此外,具有相同不饱和侧链的相应双环烯酮衍生物的光诱导环化以良好的收率和高立体选择性提供了推进烷类型的四环和三环产物。((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)。