Scheme 2. Synthesis of Enantioenriched 2-Trifluoromethyl Pyrrolidines.

Reactions were performed as described in Table 1. The yield is for both diastereomers. The diastereomeric ratio was determined by ¹⁹F NMR spectroscopic analysis of the crude product. The enantiomeric ratio was determined by HPLC analysis on a chiral stationary phase. ^b Number in parentheses is dr following column chromatography. ^c The Michael addition was performed at −10 °C for 1 h.