A process for producing a compound of formula (I) wherein a compound of formula (II) is reacted with a compound of formula (III) where in each case: R 1 represents (C 1 -C 12 )-alkyl, (C 1 -C 12 )-haloalkyl, (C 6 -C 10 )-aryl, (C 6 -C 10 )-haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 4 -C 10 )-cycloalkyl or (C 4 -C 10 )-halocycloalkyl, R 2 represents (C 1 -C 12 )-alkyl, (C 1 -C 12 )-haloalkyl, (C 6 -C 10 )-aryl, (C 6 -C 10 )-haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 4 -C 10 )-cycloalkyl or (C 4 -C 10 )-halocycloalkyl, R 3 and R 4 each independently of one another represent hydrogen, (C 1 -C 4 )-alkyl, phenyl or benzyl, R 5 represents (C 1 -C 12 )-alkyl, (C 1 -C 12 )-haloalkyl, (C 6 -C 10 )-aryl, (C 6 -C 10 )-haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 4 -C 10 )-cycloalkyl or (C 4 -C 10 )-halocycloalkyl, X represents oxygen or sulphur and n is 0 or 1, in the presence of one or more free-radical-forming substances (IV) where two separate metered streams (D1) and (D2) are metered into the reactor and these metered streams (D1) and (D2) have the following composition: metered stream (D1) comprises one or more compounds of formula (II) and one or more free-radical-forming substances (IV) and metered stream (D2) comprises one or more compounds of formula (III) and also optionally one or more compounds of formula (II) and optionally one or more free-radical-forming substances (IV), where the reaction is carried out in continuous fashion. R 1 represents (C 1 -C 12 )-alkyl, (C 1 -C 12 )-haloalkyl, (C 6 -C 10 )-aryl, (C 6 -C 10 )-haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 4 -C 10 )-cycloalkyl or (C 4 -C 10 )-halocycloalkyl, R 2 represents (C 1 -C 12 )-alkyl, (C 1 -C 12 )-haloalkyl, (C 6 -C 10 )-aryl, (C 6 -C 10 )-haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 4 -C 10 )-cycloalkyl or (C 4 -C 10 )-halocycloalkyl, R 3 and R 4 each independently of one another represent hydrogen, (C 1 -C 4 )-alkyl, phenyl or benzyl, R 5 represents (C 1 -C 12 )-alkyl, (C 1 -C 12 )-haloalkyl, (C 6 -C 10 )-aryl, (C 6 -C 10 )-haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 4 -C 10 )-cycloalkyl or (C 4 -C 10 )-halocycloalkyl, X represents oxygen or sulphur and n is 0 or 1, in the presence of one or more free-radical-forming substances (IV) where two separate metered streams (D1) and (D2) are metered into the reactor and these metered streams (D1) and (D2) have the following composition: metered stream (D1) comprises one or more compounds of formula (II) and one or more free-radical-forming substances (IV) and metered stream (D2) comprises one or more compounds of formula (III) and also optionally one or more compounds of formula (II) and optionally one or more free-radical-forming substances (IV), where the reaction is carried out in continuous fashion. metered stream (D1) comprises one or more compounds of formula (II) and one or more free-radical-forming substances (IV) and metered stream (D2) comprises one or more compounds of formula (III) and also optionally one or more compounds of formula (II) and optionally one or more free-radical-forming substances (IV), where the reaction is carried out in continuous fashion. <EOS>