Process for the preparation of gamma-butyrolactams

A process for the preparation of a C(3)-C(4)-transconfigurated .gamma.-butyrolactam of the general formula (I) ##STR38## in which R.sup.1 represents hydrogen or alkyl, aryl or aralkyl with in each case up to 10 carbon atoms and

• R.sup.2 and R.sup.3 are identical or different and represent hydrogen, alkyl, alkoxy, with in each case up to 10 carbon atoms, phenyl, benzyl, phenoxy, benzloxy, benzoyl, acetyl, trifluoromethyl, trifluoromethoxy, nitro, hydroxy, halogen, amino, carboxyl, sulpho, dialkylamino with up to 4 carbon atoms in the alkyl groups or acylamino with up to 18 carbon atoms,
• and isomers, isomer mixtures, racemates or optical antipodes of said .delta.-butyrolactam, comprising reacting a starting compound of the formula (II) ##STR39## in which R.sup.1, R.sup.2 and R.sup.3 have the above-mentioned meanings with an oxidizing agent selected from the group consisting of peroxoacetic acid, chloroperbenzoic acid, molybdenum peroxide/pyridine complex, oxygen, ozone and 2-sulphonyloxaziridine in an inert organic solvent in the presence of a base selected from the group consisting of an alkali metal alcoholate, an alkali metal amide, an alkali metal hydride, an organo-alkali metal compound, 1,5-diazabicyclo(4,3,0)non-5-ene and 1,8-diazabicyclo(5,4,0)undec-7-ene and further in the presence of a phosphite auxiliary, wherein the reaction is conducted at a temperature of -100.degree. C. to +20.degree. C., and wherein 1 to 5 moles of base are employed per mole of starting compound.