Process for the preparation of hexahydro-5-hydroxy- 4-hydroxymethyl-2H-cyclopenta[b]furan-2-one derivatives

The process for the preparation of hexahydro-5-hydroxy- 4-hydroxymethyl-2H-cyclopenta[b]furan-2-one derivatives of the general formula I in which Z denotes the R -C6H4CO-group and R denotes a hydrogen atom, a methyl group, phenyl group or optionally a nitro group, lies in reacting a halohydroxyketone of the general formula II in which X denotes a chlorine, bromine or iodine atom, with an acylating agent of the general formula R COY in which R denotes an alkyl radical having 1 to 3 carbon atoms and Y denotes a chlorine or bromine atom or the R -COO-group, in the presence of tertiary amines, with the formation of an acyl derivative of the general formula III in which R and X have the abovementioned meaning. The aryl derivative is oxidised by a peroxyacid into the corresponding delta -lactone, which is converted by the action of alkali metal hydroxides into the corresponding delta -lactone of the general formula V in which R has the above meaning. The hydroxyl group of the compound of the general formula V is protected by the group Z, which has the abovementioned meaning, with the formation of a diester, from which the Corey lactone of the general formula I is set free by selective transesterification. This synthesis is of interest in the preparation of prostaglandins.