ASYMMETRIC REDUCTION OF 2-(N-ARYLIMINO)-3,3,3-TRIFLUOROPROPANOIC ACID-ESTERS LEADING TO ENANTIOMERICALLY ENRICHED 3,3,3-TRIFLUOROALANINE

Enantiomerically enriched 3,3,3-trifluoroalanine (1) (up to 62 % ee) h as been synthesized by the asymmetric reduction of 2-(N-arylimino)-3,3 ,3-trifluoropropanoic acid esters with a chiral oxazaborolidine cataly st and subsequent oxidative removal of N-aromatic moiety with retentio n of the configuration. Detailed optimization studies revealed that th e effects of solvents, temperature, and the structural modification of the substrate were drastic on the enantioselectivity. The absolute co nfiguration of 1 was determined to be (R) by X-Ray crystallographic an alysis of the corresponding N-(S)-(+)-camphorsulfonyl derivative.