Highly enantioselective Rh-catalyzed hydrogenations with heterocombinations of pentafluorobenzyl- and methoxybenzyl-derived binaphthyl phosphites

The Rh-catalyzed hydrogenations of dimethyl itaconate and methyl acetamido acrylate using selected heterocombinations of pentafluorobenzyl- and methoxybenzyl-derived binaphthyl phosphites proved to be highly enantioselective (ee 93–99%). In these selected cases the Rh-heterocomplexes, which were formed in a statistical amount (ca. 50% by 31P NMR), turned out to be more active and selective than the two homocomplexes.