New synthesis of trifluoromethyl aldimines containing L-α-amino ester moieties and their use in Mannich-type reactions

L-α-Amino esters were considered as valuable chiral starting materials in the condensation reaction with trifluoroacetaldehyde (fluoral) ethyl hemiacetal to obtain new functionalized trifluoromethyl aldimines. Starting from these latter compounds, isovaleraldehyde was used in proline catalyzed Mannich-type addition reactions to give trifluoromethyl syn- or anti--amino alcohols bearing the L-α-amino ester function, simply by changing the reaction temperature.