NMR-STUDIES ON THE RHODIUM(I) CHELATES OF 2 2,3-BIS(O-DIPHENYLPHOSPHINO)-BETA-D-GLUCOPYRANOSIDES - POTENT CATALYSTS FOR ENANTIOSELECTIVE REACTIONS

The H-1, C-13 and P-31 NMR spectra of the 2,3-bis(O-diphenylphosphino)-beta-D-glucopyranoside rhodium(I) chelates 1 and 2 were recorded in CDCl3 solution and the spectral assignments were performed with 1D and 2D techniques. In both complexes the pyranoside ring has a chair conformation. For the seven-membered chelate ring a twist-boat conformation could be established for 1, whereas for 2 the expected twist-chair conformation was found. The phenyl groups at the P atoms show unhindered rotation about the C-phenyl-P bonds and the COD ligand seems to rotate about the Rh-COD axis slowly on the NMR time-scale.