The presence of an allylic 5α-hydroxy group in an androst-3-ene increases the proportion of addition of a borane to the adjacent C-4 compared to the unsubstituted steroid and directs the addition to the face of the alkene anti to the hydroxy group with stereochemical effects that may oppose those of the C-10β-methyl group.
与未取代的类
固醇相比,雄激素 3-烯中烯丙基 5α-羟基的存在增加了
硼烷与相邻 C-4 的加成比例,并引导加成到与羟基相反的烯烃表面具有可能与 C-10β-甲基相反的立体
化学效应。