The enantiocontrolled preparation of the trans-fused ABC ring system of norzoanthamine is described. The synthesis strategy has incorporated studies of Ireland–Claisen rearrangements of esters derived from 3,3-dimethylacrylic acid. Stereocontrol results from competing chair- and boat-like transition states. Introduction of a nitroalkene by application of a modified Henry reaction facilitates an intramolecular
描述了去甲虫胺的反式稠合ABC环系统的对映控制制备。合成策略纳入了对源自
3,3-二甲基丙烯酸的酯的爱尔兰-克莱森重排的研究。立体控制产生于相互竞争的椅子和船状过渡状态。通过应用改良的亨利反应引入硝基烯烃促进了分子内 Diels-Alder 环加成,从而有效且简单地转化为所需的共轭十酮。全功能化的 AB 环系统导致反式稠合
环己烯酮环化,通过闭环复分解反应完成 ABC 系统。