NEW BETA-AMINO ALCOHOLS DERIVED FROM L-VALINE AS CHIRAL INDUCTORS FOR ENANTIOSELECTIVE REDUCTIONS OF, AND NUCLEOPHILIC ADDITIONS TO CARBONYL-COMPOUNDS

beta-Amino alcohols derived from L-valine were used as chiral ligands in oxazaborolidine reductions of ketones. Structural modifications, such as the introduction of alkyl groups on the carbinol carbon and the nitrogen atoms, were shown to influence unfavourably the enantioselectivity. In contrast, the addition of diethyl zinc to aldehydes occurs with enhanced e.e.'s using these modified inductors, which permit to reach useful enantioselectivities with various aldehydes.