SIMPLE AND QUICK METHOD FOR SYNTHESIS OF META-ACYLATED PHENOLS

A new method for the meta acylation of anisole and its para-methyl or fluoro derivatives, is described. Addition of two trimethysilyl groups in the 2 and 5 positions (relative to the methoxy group), followed by hydrolysis affords the corresponding 5-trimethylsilyl-3-cyclohexenone s. Electrophilic substitution of the silyl group using RCOCl/2AlCl(3) at low temperature provides, after final aromatisation promoted by Pd/ C or CuBr2/LiBr, the expected meta acylated products. This mode of met a functionalization has been successfully applied to an original synth esis of ketoprofen starting from anisole.