Chemo-enzymatic synthesis of levodropropizine

Levodropropizine, an antitussive drug, was prepared in high enantiomeric excess in three steps, starting from dichloroacetone (2).Monosubstitution of 2 with sodium benzoate and subsequent baker’s yeast reduction stereoselectively afforded the correspondingchlorohydrin in 73% ee, which was converted to levodropropizine and enantiomerically enriched up to 95% ee by fractionalcrystallisation