CATALYTIC FRIEDEL-CRAFTS ACYLATION REACTIONS USING HAFNIUM TRIFLATE AS A CATALYST IN LITHIUM PERCHLORATE-NITROMETHANE

Catalytic Friedel-Crafts acylation reactions were performed by using h afnium trifluoromethanesulfonate (hafnium triflate, Hf(OTf)(4)) as a c atalyst. The catalytic activity of the Lewis acid catalyst was much im proved in lithium perchlorate-nitromethane (LiClO4-MeNO(2)) and the yi eld was up to 250,000% based on the catalyst. Various substituted benz enes reacted with acid anhydrides in the presence of a catalytic amoun t of Hf(OTf)(4) to give the corresponding aromatic ketones in high yie lds.