Access to Fluoropyrrolidines by Intramolecular Aza-Michael Addition Reaction

Study
of the intramolecular aza-Michael addition reaction from
an aminofluorovinylsulfone opens a new route for the synthesis of
pyrrolidine derivatives. An unexpected diastereoselective cyclization
reaction was observed, leading preferentially to the anti-N-benzylpyrrolidine sulfone. The resulting sulfone
was reacted with aldehydes to access β-substituted α-fluoroalkenyl
pyrrolidines in one step.