An efficient catalytic asymmetric route to 1-aryl-2-imidazol-1-yl-ethanols

The asymmetric hydrogenation of 1-aryl-2-imidazol-1-yl-ethanones offers a concise route to homochiral 1-aryl-2-imidazol-1-yl-ethanols. Catalytic asymmetric transfer hydrogenation with formic acid using [(R,R)-TsDPEN]Ru(Cymene)Cl as precatalyst was shown to be effective in this transformation. Preliminary process development showed that the hydrogenation could be carried out under mild conditions at a molar substrate-to-catalyst (SIC) ratio of 1000-2000.