Process for the preparation of (S)-4-fluoromethyl-dihydro-furan-2-one useful in the preparation of the DPP-IV inhibitor (S)-1 ((2S,3S,11bS)-2-amino-9,10-dimethoxy-1,3,4,6,7, 11b-hexahydro-2h-pyrido[2,1-a] isoquinolin-3-yl)-4-fluoromethyl-pyrrolidin-2-one
Several new routes are reported for the synthesis of (S)-3-fluoromethyl-gamma-butyrolactone. An asymmetric hydrogenation-based synthesis was chosen as the enabling route to produce the lactone on a 10-kg scale. A superior stereoselective route starting from (S)-tert-butyl glycidyl ether which afforded the desired lactone in three steps with similar to 50% overall yield was finally selected for further development and production.
PREPARATION OF (S)-4-FLUOROMETHYL-DIHYDRO-FURAN-2-ONE