Polyenine compounds are provided having the naturally occurring geometry and a group which in the presence of acid initiates a carbocation cyclization to a steroid or A-nor-steroid structure, particularly the pregnane parent structure. The compounds are formed for the most part by condensation of two units prepared from readily available small molecules and are joined to form a polyenine, usually having a substituted carbocyclic ring which upon contact with a Lewis acid catalyst (includes protonic) cyclizes directly to provide the 5-membered D ring as well as substitution at the C-20 position.
提供具有自然几何形态和在酸存在下引发碳阳离子环化至类
固醇或A-去甲类
固醇结构的基团的多烯酰胺化合物,特别是孕烷母体结构。这些化合物大部分由两个从易得小分子制备的单元缩合而成,并连接形成多烯酰胺,通常具有取代的碳环,接触Lewis酸催化剂(包括质子)后直接环化,从而提供5-成员D环以及C-20位置的取代。