Patent ID: 8586750

Claim:
A process for preparing compounds of the formula (I) wherein R 1 is C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl, C 2 -C 6 -alkenyl, C 3 -C 10 -cycloalkyl or benzyl, where the two last mentioned radicals are unsubstituted or have 1, 2 or 3 substituents independently of one another selected from the group consisting of halogen, CN, nitro, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 1 -C 4 -alkoxy and C 1 -C 4 -haloalkoxy; R 2 and R 3 independently of one another are C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl, C 2 -C 6 -alkenyl, C 3 -C 10 -cycloalkyl or benzyl, where the two last mentioned radicals are unsubstituted or have 1, 2 or 3 substituents independently of one another selected from the group consisting of halogen, CN, nitro, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 1 -C 4 -alkoxy and C 1 -C 4 -haloalkoxy; or R 2 together with R 3 and the nitrogen atom to which the two radicals are attached are an optionally substituted 5- to 10-membered heterocyclic radical which, in addition to the nitrogen atom, may contain a further 1, 2 or 3 heteroatoms selected from the group consisting of O, N and S as ring members; R 4 is hydrogen, fluorine or chlorine; and X 1 and X 2 independently of one another are fluorine or chlorine; comprising reacting a compound of the formula (II) with a compound of the formula X 1 X 2 R 4 C—C(═O)—F in the presence of at least one alkali or alkaline earth metal fluoride.