 Better stereoselectivity is achieved when one substituent is larger than the other (see Flippin-Lodge angle).An antibacterial levofloxacin is synthesized using (R)-1,2-propandiol, which is synthesized from hydroxyacetone using Noyori asymmetric hydrogenation (Takasago Co./Daiichi Pharmaceutical Co.).An antibiotic carbapenem is also prepared using Noyori asymmetric hydrogenation via (2S,3R)-methyl 2-(benzamidomethyl)-3-hydroxybutanoate, which is synthesized from racemic methyl 2-(benzamidomethyl)-3-oxobutanoate by dynamic kinetic resolution.