Patent ID: 7498448

Claim:
A process for preparing (S)-3-methylamino-1-(thien-2-yl)propan-1-ol of the formula I-S comprising a) reacting thiophene is with a β-halopropionyl halide or an acryloyl halide in the presence of a Lewis acid to give a 3-halo-1-(thien-2-yl)propan-1-one, with a hydrogen halide being passed in simultaneously or after the reaction has taken place, but before the reaction product is isolated, and b) reducing the propanone obtained in step a) and then reacting with methylamine; wherein step b) is carried out in the presence of a dehydrogenase which exhibits selectivity with regard to the formation of (S)-3-methylamino-1-(thien-2-yl)propan-1-ol.