Aluminum trifluoromethanesulfonate

White powder

Lewis acid used as a catalyst for Friedel–Crafts, ketalization, nucleophilic substitution, hydroalkoxylation, methoxycarbonyla- tion, rearrangement, and epoxide ring-opening reactions.

Aluminum trifluoromethanesulfonate is used in pharmaceutical intermediates.

Can be prepared from aluminum trichloride and tribromide by heating with triflic acid in anhydrous conditions. Preparations from triethylaluminum, aluminum carbide, and aluminum isopropoxide have also been described.

Friedel-Crafts Reactions.
Aluminum trifluoromethanesulfonate has been used for the Friedel-Crafts alkylation reaction of toluene with isopropyl and tert-butyl chlorides (eq 1), and for theacylationofbenzeneandtoluenewithacetylandbenzoylchlo- rides in low to moderate yields. Intramolecular Friedel-Crafts acylation of an aromatic compound with Meldrum’s acid has also been reported using catalytic amounts of Al(OTf) 3 . Acylation of 2-methoxynaphthalene with acetic anhydride has been reported using Al(OTf) 3 and lithium perchlorate as an additive to afford the corresponding 6-acetylated adduct in 83% yield. Effective acylation of arenes with carboxylic acids has also been disclosed using polystyrene-supported Al(OTf)3.