Asymmetric Synthesis of (R)- and (S)-Moprolol

Abstract A simple and effective procedure for the enantioselective synthesis of ( R )- and ( S )-Moprolol was described. The key step was the asymmetric synthesis of enantiopure ( R )- and ( S )-guaifenesin, which were synthesized from enantioenriched ( R )-3-chloro-1,2-propanediol and ( S )-epichlorohydrin via kinetics of hydrolysis resolution of racemic epichlorohydrin by chiral Salen-Co III complex. The e.e. values of both the optical compounds were above 98%, and the chemical structures of the target compounds were confirmed by 1 H NMR, 13 C NMR, IR, and MS.