Regio- and stereocontrolled synthesis of novel steroidal isoxazolines: A new route to the formation of selectively modified steroid side chains
作者:Halina Zhylitskaya、Raisa Litvinovskaya、Alexander Baranovsky、Václav Eigner、Bohumil Kratochvíl、Pavel Drašar、Vladimir Khripach
DOI:10.1016/j.steroids.2013.04.017
日期:2013.9
1,3-Dipolar cycloaddition reaction of acetonitrile oxide to cis- and trans-22-hydroxy-24-alkoxycarbonyl-Δ(23)-steroids is investigated. An unusual stereochemical course of the cycloaddition, leading to the same set of the isoxazoline adducts for both (Z)- and (E)-disubstituted olefins is revealed. It is shown, the reaction is regioselective and all possible 4',5'-diastereoisomers of resulting isoxazolines
研究了乙腈氧化物与顺式和反式 22-羟基-24-烷氧基羰基-Δ(23)-类固醇的 1,3-偶极环加成反应。揭示了环加成的一个不寻常的立体化学过程,导致 (Z)- 和 (E)- 二取代烯烃的相同组异恶唑啉加合物。结果表明,该反应是区域选择性的,所得异恶唑啉的所有可能的 4',5'-非对映异构体都可以通过环加成到合适的烯烃来制备作为主要产物。关键化合物的结构已通过 X 射线和 2D 核磁共振分析确认。