An Efficient and Green Synthesis of 1‐Indanone and 1‐Tetralone via Intramolecular Friedel–Crafts Acylation Reaction

Metal‐triflate‐catalyzed intramolecular Friedel–Crafts acylation of 3‐arylpropanoic and 4‐arylbutanoic acids in triflate‐anion ionic liquids under monomodal microwave irradiation is reported. The environmentally benign synthetic procedure allows the formation of cyclic ketones in good yields within a short reaction time. The catalytic metal triflate in triflate‐anion ionic liquids can be easily recovered and reused several times without significant loss of the catalytic performance.