THE CATALYTIC FRIEDEL-CRAFTS ACYLATION REACTION STARTING FROM AROMATIC-COMPOUNDS AND FREE CARBOXYLIC-ACIDS (OR THEIR TRIMETHYLSILYL ESTERS) BY PROMOTION OF SILICON(IV) CATIONIC SPECIES VIA MIXED ANHYDRIDES

In the presence of active cationic species generated from silicon(IV) chloride and silver perchlorate, carboxylic acids or their trimethylsilyl esters react with p-trifluoromethylbenzoic anhydride to form corresponding mixed anhydrides in situ. Then the catalytic Friedel-Crafts acylation reaction between initially formed mixed anhydrides and coexisted aromatic compounds smoothly proceeds at room temperature to afford the corresponding aromatic ketones in high yields. The above two sequential reactions are effectively promoted by the active silicon(IV) catalyst under mild conditions.