Stereoselective Synthesis and Absolute Configuration of (1′R,3R,4R)‐4‐Acetoxy‐3‐ (2′,2′,2′‐trifluoro‐1′‐hydroxyethyl)‐azetidin‐2‐one.

Abstract The title compound 3, an intermediate in the synthesis of fluorocarbapenems, is obtained with high stereocontrol by the condensation of (R)-(+)-ethyl 4,4,4-trifluoro-3-hydroxybutanoate with N-trimethylsilyl cinnamylidenimine. X-Ray diffraction analysis of the condensation product and chemical correlations allowed the unambiguous determination of the absolute configuration.