Enantioselective hydrogenation in the presence of the rhodium(i) complex with (+)-4S,5S-N4,N4,N5,N5,2,2-hexamethyl-1,3-dioxolane-4,5-dimethaneamine

Hydrogenation of -acetamidocinnamic and itaconic acids and their esters was carried out in the presence of the cationic Rh^I triflate complex with (+)-4S,5S-N⁴,N⁴,N⁵,N⁵,2,2-hexamethyl-1,3-dioxolane-4,5-dimethaneamine (DIODMA). The optical yields depended on the nature of the solvent and the hydrogen pressure and reached 30%. The catalytically active forms of the complexes and their transformations in the presence of phosphines, molecular hydrogen, and the substrate were studied by ¹H and ³¹P NMR spectroscopy.