Patent ID: 6974834

Claim:
A process for the preparation of enantiomerically enriched (1S,4R) 1-acetoxy-4-hydroxycyclopent-2-ene comprising the steps of: a) determining the water content of pancreatin; b) mixing pancreatin, cis -1,4-dihydroxycyclopent-2-ene, vinyl acetate, and triethylamine in tetrahydrofuran; c) adjusting the water content of the mixture such that the water content is 5-7% of the weight of the pancreatin; d) maintaining a reaction temperature of −40° C. to +40° C. with stirring until the reaction is substantially complete; e) concentrating the reaction mixture f) dissolving the residue in methyl-t-butylether, optionally treating the mixture with activated charcoal and filtering the mixture; and g) precipitating (1S,4R) 1-acetoxy-4-hydroxycyclopent-2-ene with an enantiomeric purity of 95-99% by the addition of a hydrocarbon solvent at 0-15° C.