Unexpected change of the sense of the enantioselective hydrogenation of ethyl pyruvate catalyzed by a Pt-alumina-cinchona alkaloid system.
In the enantioselective hydrogenation of ethyl pyruvate (EtPy) over beta-isocinchonine (beta-ICN) modified Pt-alumina catalysts, the major enantiomer was (R)-ethyl lactate ((R)-EtLt (ee 50%)) in toluene, while in AcOH (S)-EtLt (ee 60%) was formed; the (R) configuration is opposite to what is expected from the absolute configuration of the cinchonine backbone.
Bartók
M
M
Organic Catalysis Research Group of the Hungarian Academy of Sciences, University of Szeged, Dóm tér 8 H-6720, Hungary. bartok@chem.u-szeged.hu
Sutyinszki
M
M
Felföldi
K
K
Szöllósi
Gy
G