A variety of highly functionalized polycyclic isoxazoles are prepared by a two-step protocol: (1) 1,3-dipolar cycloaddition of o,oâ²-disubstituted benzonitrile oxides to para-quinone mono-acetals, then (2) dehydrogenation. The cycloaddition proceeds in a regioselective manner, favouring the formation of the 4-acyl cycloadducts, which are suitable intermediates for the synthesis of semi-aromatized polycyclic targets derived from polyketide type-II biosynthesis.
我们采用两步法制备了多种高度官能化的多环
异噁唑:(1) o,oâ²-二取代苯腈氧化物与
对苯醌单
乙醛的 1,3-二极环化反应,然后 (2) 脱氢反应。该环化反应以区域选择性的方式进行,有利于形成 4-酰基环化产物,这些环化产物是合成来自多酮 II 型
生物合成的半芳香化多环目标物的合适中间体。