VERFAHREN ZUR HERSTELLUNG VON CYCLISCHEN 1,2-CIS-DIOLEN AUS CYCLISCHEN 1,2-EPOXIDEN

1. Process for the preparation of cyclic 1,2-cis-diols of the general formula I see diagramm : EP0080658,P10,F3 wherein the carbocyclic ring contains 5-7 carbon atoms and R**1 and R**2 are identical or different and independently of each other represent hydrogen or optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl radicals, n represents 1, 2, 3 or 4 and R represents hydrogen, hydroxyl, halogen, cyano or optionally substituted alkyl cycloalkyl, alkenyl, aryl, aralkyl, alkoxy, alkoxycarbonyl, aryloxy, alkylthio, arylthio or heterocyclic radicals, it being possible, in the case n > 1, for the radicals R to be identical or different, and it being possible for 2 adjacent radicals R, optionally also twice, to represent a double bond, characterised in that cyclic 1,2-epoxides of the general formula II see diagramm : EP0080658,P11,F1 wherein the carbocyclic ring contains 5-7 carbon atoms and R**1 , R**2 , n and R have the abovementioned meaning, are reacted with carbon dioxide in the presence of a carbonation catalyst under pressures of 20-200 bars and at temperatures between 100 and 300 degrees C, the pressure being kept constant by pumping in further carbon dioxide until a decrease in pressure is no longer observed, - (1st stage) - and the cyclic 1,2-cis-carbonates formed in this reaction, of the general formula (III) see diagramm : EP0080658,P11,F2 wherein the carbocyclic ring again contains 5-7 carbon atoms and R**1 , R**2 , n and R have the abovementioned meaning, are hydrolysed with water, aqueous salt solutions, dilute aqueous acids or bases or solvolysed with a solution of an alcoholate in an alcohol, in each case at an elevated temperature, and if appropriate, under an elevated pressure (2nd stage).