Optically pure ethyl 5-hydroxycyclopent-1-enecarboxylate has been obtained with its acetate in both enantiomeric forms in excellent optical yields from racemic ethyl 5-hydroxycyclopent-1-enecarboxylate by lipase-mediated kinetic resolution. The optically pure (R)-enantiomer thus obtained has been transformed into two naturally occurring iridoid monoterpenes, (+)-mitsugashiwalactone and (-)-dolichodial.