Asymmetric synthesis of ibuprofen and ketoprofen

Abstract ( S )-2-[4′-(2″-Methylpropyl)phenyl]propanoic acid (ibuprofen) and ( S )-2-(3′-benzoylphenyl)propanoic acid (ketoprofen) have been synthesised in high enantiomeric excess. Control of the stereochemistry was achieved by a combination of Sharpless epoxidation followed by catalytic hydrogenolysis of the introduced benzylic epoxide oxygen bond.