Achiral β-amino alcohols as efficient ligands for the ruthenium-catalysed asymmetric transfer hydrogenation of sulfinylimines

Some achiral beta-amino alcohols have been shown as efficient ligands for the ruthenium-catalysed asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)imines in isopropanol. The ruthenium complex prepared from [RuCl(2)(p-cymene)](2) (2.5 mol %) and 2-amino-2-methyl-1-propanol (5 mol %) leads to cc-branched chiral primary amines with very high optical purities (up to 98% ee) by the diastereoselective reduction of the imines followed by removal of the sulfinyl group under mild acidic conditions. Short reaction times (2-3 h) were needed to complete the reduction reactions when they were performed at 50 degrees C. 2010 Elsevier Ltd. All rights reserved.