Catalytic sugar-assisted transfer hydrogenation with Ru(II), Rh(III) and Ir(III) halfsandwich complexes

Abstract

The application of halfsandwich ruthenium(II), rhodium(III) and iridium(III) complexes of four different methyl 2,3-diamino-4,6-O-benzylidene-2,3-dideoxy-α-D-hexopyranosides and a methyl 2-amino-3-tosylamido-α-D-glucopyranoside as catalyst precursors in asymmetric transfer hydrogenation of acetophenone is reported. The configuration of the hexopyranosides and the type of arene ligands determine the formation of R- or S-1-phenylethanol up to 66% ee. A large influence of the substitution pattern of the arene ligands on the extent of the enantiomeric excess is demonstrated. The results are interpreted by means of DFT calculations.