The enantioselective hydrogenation of a variety of a-keto acetals to the corresponding a-hydroxy acetals with Pt catalysts modified with cinchonidine derivatives is described with ees up to 97% and high reaction rates, and the influence of the substrate structure, the modifier and the reaction conditions (catalyst, solvent, temperature, pressure, modifier concentration) was investigated in some detail.

The hydrogenation of carboxylic acid derivatives at room temperature was investigated. With a mixed Rh/Pt oxide (Nishimura catalyst), low to medium activity was observed for various α‐amino and α‐hydroxy esters. At 100 bar hydrogen pressure and 10% catalysts loading, high yields of the desired amino alcohols and diols were obtained without racemization. The most suitable α‐substituents were NH2, NHR, and OH, whereas β‐NH2 were less effective. Usually, aromatic rings were also hydrogenated, but with the free bases of amino acids as substrates, some selectivity was observed. No reaction was found for α‐NR2, α‐OR, and unfunctionalized esters; acids and amides were also not reduced under these conditions. A working hypothesis for the mode of action of the catalyst is presented.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.