alpha,alpha-disubstituted-alpha-nitroketones are reduced to the corresponding trisubstituted nitro alcohols in good to excellent yield and enantiomeric excess by borane-dimethylsulfide in the presence of a chiral oxazaborolidine catalyst. Reduction of the nitro alcohols to the corresponding amino alcohols and their subsequent conversion to enantiomerically enriched 4,4,5-trisubstituted oxazoldinones
A variety of hindered alpha-trisubstituted optically active secondary alcohols has been converted into their enantiomers by treating the corresponding triflates with KNO2 in DMF in the presence of 18-crown-6 at room temperature.
Baker’s yeast reduction of nitro- and imide-containing ketones gives the corresponding secondary alcohols in good yields with excellent optical purity. Among the imide groups examined, the ketones with saccharin moiety give the products in the best chemical and optical yields.