Oxidation of commercially available 9-fluoroprednisolone (I) with sodium bismuthate gives the ketone (II), which is reacted with methanethiol in a mixture of dichloromethane and acetic acid in the presence of boron trifluoride etherate to give the thioketal (III). Acetylation of (III) with acetic anhydride in pyridine containing 4-dimethylaminopyridine gives the acetate (IV), which is heated in diethylbenzene to give the vinyl sulfide (V). The addition of ethanethiol to (V) at low temperatures in the presence of boron trifluoride etherate or trifluoroacetic acid in dichloromethane proceeds with high stereoselectivity to give the thioketal (VI), which is deacetylated with sodium hydroxide in methanol to give tipredane.