posted on 2012-06-15, 00:00authored byHyeon-Kyu Lee, Soyeong Kang, Eun Bok Choi
Each of the enantiomers of both norephedrine and norpseudoephedrine
were stereoselectively prepared from the common, prochiral cyclic
sulfamidate imine of racemic 1-hydroxy-1-phenyl-propan-2-one by employing
asymmetric transfer hydrogenation (ATH) catalyzed by the well-defined
chiral Rh-complexes, (S,S)- or (R,R)-Cp*RhCl(TsDPEN), and HCO2H/Et3N as the hydrogen source. The ATH processes are carried
out under mild conditions (rt, 15 min) and are accompanied by dynamic
kinetic resolution.