The catalytic Fries rearrangement and o-acylation reactions using group 3 and 4 metal triflates as catalysts

Group 3 and 4 metal triflates (Sc(OTf)(3), TiCl(OTf)(3), Zr(OTf)(4), and Hf(OTF)(4)) were found to be efficient catalysts in the Fries rearrangement of phenyl or 1-naphthyl acylates. It was also found that the o-acylation (direct acylation) reactions of phenols and 1-naphthols with acid chlorides proceeded smoothly in the presence of the triflates. Both reactions were successfully carried out using small amounts of the triflates (catalytically), and comparison of catalytic activities of these metal triflates in these reactions is discussed.