Fluorodeoxygenation of Proline: Optically Active 2-Trifluoromethylpyrrolidine and Its Chromophoric Derivatives.

1. The fluorodeoxygenation of (S)-proline by the action of sulfur tetrafluoride in hydrogen fluoride to (-)-2-trifluoromethylpyrrolidine was realized without affecting the carbon of the chiral center. 2. According to PMR data, 2-trifluoromethylpyrrolidine, its N-chloro derivative, and 1-chloro-2-methoxycarbonylpyrrolidine exist preferentially in the conformation with the pseudoequatorial orientation of the substituent at position 2.