Preparation of esters

A process for the preparation of an ester of the formula ##STR5## wherein Ar represents a phenoxy substituted phenyl group and R an alkyl group optionally substituted by halophenyl or alkylphenyl or a cyclopropyl group optionally substituted by alkyl, halogen, isobutenyl, dichlorovinyl or dibromovinyl, which process comprises contacting an aromatic aldehyde of the formula ArC(O)H and a (cyclo)aliphatic aryl halide of the formula RC(O)Hal, in which formulas Ar and R have the same meaning as in the formula I and Hal represents a halogen atom having an atomic number from 9 to 53, inclusive, with water, a water-soluble cyanide, a substantially water-immiscible aprotic solvent and a macrocyclic polyether phase transfer catalyst containing a total of from 4 to 80 atoms and 14 to 28 ring atoms at least 4 of which are oxygen atoms and recovering the desired ester from the reaction mixture.