From 4β- as well as from 2β-hydroxy-steroids 19-hemiacetal derivatives are formed in the «hypoiodite reaction», especially with lead tetraacetate and iodine, whereas 6β-hydroxy-steroids give 6β,19-ethers exclusively(1). This behaviour is explained on the basis of the differences in the relative orientation of the hydroxyl groups towards the conformationally fixed 19-CH2I group in the iodohydrin intermediates
在“次
碘酸反应”中,由4β-和2β-羟基-甾族化合物形成19-
半缩醛衍
生物,特别是与四
乙酸铅和
碘形成,而6β-羟基甾族化合物仅生成6β-19-醚(1)。根据
碘醇中间体中羟基相对于构象固定的19-CH 2 I基团的相对取向的差异来解释这种行为。