Organic base-catalyzed stereodivergent synthesis of (R)- and (S)-3-amino-4,4,4-trifluorobutanoic acids

Organic base-catalyzed reaction of (S)-N-tert-butanesulfinyl (3,3,3)-trifluoroacetaldimine with dialkyl malonates was found to be effective for synthesis of both (S,S-S) and (R,S-S) beta-amino-malonates in high yield with good to excellent diastereoselectivity (76-98% de). The products of this Mannich reaction provide direct access to beta-trifluoromethyl-beta-alanine of either (R) or (S) absolute configuration.