New asymmetric approach to β-trifluoromethyl isoserines

• Published in: RSC advances Vol. 3; no. 18; pp. 6479 - 6484
• Main Authors: Shevchuk, Michael V., Kukhar, Valery P., Röschenthaler, Gerd-Volker, Bassil, Bassem S., Kawada, Kosuke, Soloshonok, Vadim A., Sorochinsky, Alexander E.
• Format: Journal Article
• Language: English
• Published: 01.01.2013
• Subjects: Asymmetry; Derivatives
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c3ra40687c

Enantiomerically pure N,O-protected beta -trifluoromethyl isoserine derivatives of (2S,3S)- and (2R,3S)-absolute configurations have been easily prepared by diastereoselective addition of the enolates, derived from O-protected alpha -hydroxyacetates, to (S)-N-tert-butanesulfinyl (3,3,3)-trifluoroacetaldimine with high combined yield and good syn/antistereoselectivity. To explain the unusual stereochemical outcome in these reactions a mechanistic rationale involving the addition of Z-enolates to (S)-imines via open transition states was proposed on the basis of the experimental data. Elaboration of these products via chemoselective manipulation of the protecting groups has been demonstrated.