Synthesis and Ruthenium‐Catalyzed Enantioselective Hydrogenation of 3‐O‐Substituted 1,3‐Dihydroxypropan‐2‐ones. Part 2

Abstract A number of 3‐ O ‐substituted 1,3‐dihydroxypropan‐2‐ones have been synthesized in view of their potential use as prochiral precursors of optically active glycerols. Indeed, the oxo‐ethers have been reduced to the corresponding 3‐ O ‐substituted glycerols via chiral Ru complexes derived from ( S )‐binap, ( =(−)‐( S )‐2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthalene) with enantiomeric excesses up to 93%. The steric course of the catalytic reduction appears to be essentially dependent on the steric encumbrance of the substituents; indeed, a dramatic increase of the enantiomeric excess is observed when the bulky trityl group is substituted by the less encumbering benzyl or octadecyl groups.