Meldrum intramolecular Friedel-Crafts acylation

Pillion, E. and Fishlock, D. 2003. Convenient access to polysubstituted 1-indanones by Sc(OXf)3-catalyzed intramolecular Friedel-Crafts acylation of benzyl Meldrum s acid derivatives. Org. Lett. 5 4653 656. 

Intramolecular Friedel-Crafts acylation of enolizable benzyl Meldrum acids 22 wifh scandium triflate (7%-12% mol) in refluxing nitromethane or acetonitrile is a powerful tool for the preparation of a variety of indan-l-ones 23 (Table Meldrum acid derivatives, mono- and dis-... 

The intramolecular Friedel-Crafts acylation of benzyl Meldrum s acids was catalyzed by Sc(OTf)3 under mild conditions (Scheme 12.25) [54]. Depending on the substituents of the benzyl Meldrum s acids, yields of 1-indanones ranged from 13 to 83%. 

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 the acylation of benzene and toluene with acetyl and benzoyl chlorides 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. ... 

Fillion, E., Fishlock, D., Wilsily, A., and Goll, J. M. 2005. Meldrum s Acids as acylating agents in the catalytic intramolecular Friedel-Crafts reaction. /. Org. Chem. 70 1316-1327. 

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