Conjugate addition of benzylmagnesium chloride (II) to unsaturated ketone (I) in the presence of cuprous iodide-dimethyl sulfide complex afforded the 2-benzyl derivative (III). Then, the ester function was saponified with NaOH in MeOH to give the title acid. Resolution of the enantiomers was effected by fractional crystallization of the ephedrine salts.