THE CATALYTIC ASYMMETRIC ALDOL REACTION OF SILYL KETENE ACETALS WITH ALDEHYDES IN THE PRESENCE OF A CHIRAL BORANE COMPLEX - NITROETHANE AS A HIGHLY EFFECTIVE SOLVENT FOR CATALYTIC CONDITIONS

Catalytic asymmetric aldol reaction of silyl ketene acetals with aldehydes in the presence of 20 mol % of the chiral borane reagent, prepared in situ from the p-nitrobenzenesulfonamide of (S)-valine and BH3.THF complex, gave beta-hydroxy carboxylic acid esters in good chemical yields along with excellent enantioselectivity under conditions that employ nitroethane as an effective solvent.