Patent ID: 7956201

Claim:
A process for the preparation of (S)-4-fluoromethyl-dihydro-furan-2-one of the formula comprising the steps: a) conversion of a glycidyl ether of the formula wherein R 1a is a protecting group, with a fluoride salt to provide a fluoro hydrin of formula wherein R 1a is as defined above; b) esterification of the hydroxy group in the fluoro hydrin of the formula IV with a sulfonic acid derivative; c) ester substitution with a dialkylmalonate of the formula wherein R 1b is lower alkyl or lower phenylalkyl, in the presence of a base to provide an intermediate of the formula wherein R 1a and R 1b are as defined above, followed by d) cyclization, hydrolysis and decarboxylation under acidic conditions.