The process for preparing 4-fluoro-proline derivative

PROBLEM TO BE SOLVED: To provide a method for industrially producing a 4-fluoroproline derivative being an important intermediate for a medicine. SOLUTION: The method for producing a 4-fluoroproline derivative comprises reacting a 4-hydroxyproline-protected compound with trifluoromethanesulfonyl fluoride in the presence of an organic base such as triethylamine, lutidine, collidine, etc., and (a salt or a complex composed of an organic base such as trimethylamine, pyridine, etc., and hydrogen fluoride). The first characteristic excellently advances dehydroxyfluorination reaction of a 4-hydroxyproline-protected compound by using trifluoromethanesulfonyl fluoride as a perfluoroalkanesulfonyl fluoride. The second characteristic excellently advances the dehydroxyfluorination reaction even in the presence of a fluorinating agent such as triethylamine-hydrogen trifluoride complex or (a salt or a complex composed of an organic base such as pyridine, etc., and hydrogen fluoride) except diisopropylethylamine-hydrogen trifluoride complex. COPYRIGHT: (C)2006,JPO&NCIPI