| Acid catalysis is an important area and still remains a hot topic in organic synthesis. Using usual acids to superacids, we can carry out novel organic transformations under mild conditions. By using trifluoromethanesulfonic acid, Friedel-Crafts cycli-acyalkylation and hydroxyalkylation were achieved and tetralones, indanones and alpha-trifluoromethylphenyl alcohols were obtained in good to excellent yields. Also gallium tris(trifluoromethansulfonate), a strong, stable and recyclable solid Lewis acid, is prepared and its properties and use in Friedel-Crafts acylation, alkylation, Beckman rearrangement and Ritter reactions are discussed. Friedel-Crafts acylations using ammonium carboxylate salts and triflic anhydride were also studied and the acid catalyzed Friedel-Crafts reactions with trifluoromethyl imine were also investigated. |
