Ruthenium catalysed asymmetric transfer hydrogenation of fluorinated ketones

We have recently reported the asymmetric reduction, of a series of -fluoroacetophenones using Corey?s proline based catalyst (R)-MeCBS.[1] The product alcohols were obtained in high enantiomeric excess and yield. To develop catalytic and more environmental friendly processes, asymmetric transfer hydrogenations (ATH) have now been investigated.[2] The benefits of these reduction systems are that cheap and safe reductive agents as i-PrOH and formic acid can be used. Moreover, reductions can be performed in water and also in the presence of air. The proposed catalytic mechanism is shown in Scheme 1.[3] The catalysts were constructed from [RuCl2(mesitylene)]2 and [RuCl2(p-cymene)]2 complexed with chiral diamine ligands. The poster presents selected results from asymmetric transfer hydrogenation of fluorinated ketones using catalysts 1-4 in different medias.