SYNTHESES OF (S)-FENFLURAMINE FROM (R) OR (S)-1-[3-(TRIFLUOROMETHYL)PHENYL]PROPAN-2-OL

(R) and (S)-1-[3-(trifluoromethyl)phenyl]propan-2-ol 3 are useful inte rmediates in the synthesis of fenfluramine (S)-1. They can be obtained from optically active propylene oxide (R) or (S)-7. The alcohol (R)-3 was transformed in two steps into (S)-fenfluramine using the action o f ethylamine on a sulfonate (R)-4. We describe a new one-pot synthesis for (S)-fenfluramine from the azide (S)-5, which was obtained from th e alcohol (R)-3 in two steps. We also propose an original and rapid pr ocedure to transform the alcohol (S)-3 into (S)-fenfluramine via the c hloride (R)-14 and the azide (S)-5, without preliminary inversion of t he alcohol. All of these reactions have been achieved without any loss of chirality.