Ru-Catalyzed Asymmetric Hydrogenation of Racemic Aldehydes via Dynamic Kinetic Resolution: Efficient Synthesis of Optically Active Primary Alcohols

Catalytic asymmetric hydrogenation is one of the most elegant and reliable methods for the preparation of optically active compounds and has been widely used in industry.1 Among the numerous chiral catalysts developed in past decades, the Noyori [RuCl2(BINAP)(diamine)] catalyst has proved to be the most efficient, catalyzing the hydrogenation of prochiral ketones with excellent enantioselectivity with an extremely high turn-over number.2 Using different [RuCl2(diphosphine)(diamine)] catalysts, a variety of chiral secondary alcohols now can be easily synthesized from the hydrogenation of prochiral ketones in high enantiomeric excesses.3 Although the chiral primary alcohols are exceedingly significant compounds for both academic research and industrial production,4 few catalytic methods for their synthesis by asymmetric hydrogenation have appeared in the literature.5 In the catalytic asymmetric hydrogenation of prochiral ketones