Reduction of smilagenin acetate (Va) using a boron trifluoride etherate-lithium aluminum hydride reagent, followed by hydrogen peroxide oxidation and acetylation, was found to yield: 3±-ethoxysmilagenin (Vb), 3²-ethoxydihydrosmilagenin acetate (Via), dihydrosmilagenin diacetate (VIb), and a complex mixture of partially acetylated products. Similar reaction conditions were employed to convert dihydrodiosgemn (II) to dihydrochlorogenin (III). Boron trifluoride etherate-lithium aluminum hydride reduction of 3²-acetoxy-5±-cholestane and 3²:-acetoxy-5a-Ianostane (Villa) was shown to yield the corresponding 3²-ethoxy (e.g., VTIIb) derivatives.
ASJC Scopus subject areas
- Organic Chemistry