Patent ID: 7034181
Filing Date: 2006-04-25
Classification: C07C

Abstract:
1. A process for preparing o-chloromethylbenzoyl chlorides of the formula I in which R 1 to R 4 are identical or different and are hydrogen, C 1 –C 4 -alkyl, halogen or trifluoromethyl, by reacting benzo-fused lactones of the formula II in which R 1 to R 4 are as defined above with thionyl chloride, which comprises carrying out the reaction in the presence of catalytic amounts of a Lewis acid and catalytic amounts of a phosphine derivative of the formula III in which R′ to R′″ are identical or different and are C 1 –C 10 -alkyl or unsubstituted or C 1 –C 4 -alkyl-substituted phenyl, the index n is 0 or 1 and X is oxygen or two singly attached chlorine atoms, wherein the Lewis acid is a boron compound.