The synthesis of enantiomerically pure decalinic structures, advanced intermediates for the synthesis of the hexahydronaphtalen part of mevinic acids, is described. The key steps are the intramolecular Diels-Alder cycloaddition of a suitably substituted sugar enone obtained via the Ferrier rearrangement of tri-O-acetyl-D-glucal with the appropriate alcohol representing the diene part of the system. Chemical manipulation of the resulting, diastereomerically pure, cycloadduct led to a 5,6-unsaturated carbohydrate which was submitted to the Ferrier carbocylization. This reaction proved difficult likely because of the embedding of the aglycon in a cycle, the hydration product of the double bond being the main product. This compound was in turn transformed into the decalinic structures by treatment in basic medium. The inverse strategy, Ferrier carbocyclization followed by IMDA of an enone and a diene linked via an ester bond was unsuccessful.Key words: Intramolecular Diels-Alder reaction, enantiomerically pure decalin, Ferrier carbocyclization, carbohydrates.
描述了合成对映纯十环结构的过程,这些结构是合成梅维酸中六氢萘部分的先进中间体。关键步骤是通过Ferrier重排法获得适当取代的糖烯酮,再通过适当醇的内分子Diels-Alder环加成来表示系统的二烯部分。对结果的立体异构体纯度的化学操作导致了一个5,6-不饱和碳水化合物,该化合物经过Ferrier碳环化。这个反应很难进行,可能是因为糖苷原子团嵌入在一个环中,双键的水合产物是主要产物。然后,通过在碱性介质中处理,将这种化合物转化为十环结构。反向策略,即Ferrier碳环化,然后是通过酯键连接的烯酮和二烯进行IMDA,但未成功。关键词:内分子Diels-Alder反应,对映纯十环,Ferrier碳环化,碳水化合物。