Quantitative and Stereospecifk Dihydroxylations of Δ~5-Steroids: A Green Synthesis of Plant Growth Hormone Intermediates

摘要

Dihydroxylated Δ~5-steroids are key intermediates in preparing steroids bearing a 5α-hydroxy-6-oxa moiety, which are plant growth hormones. Quantitative and stereospecific dihydroxylations of Δ~5-steroids have been realized, using H2O2 catalyzed by KI and H2SO4 at 80 °C in aqueous dioxane. The workup consisted only of concentrating the solvents and filtering the products; no chromatography was needed. The reaction conditions tolerate various functional groups on the Δ~5-steroids. A mechanism for this reaction is proposed and the reason that the reaction is quantitative and stereospecific is explained.