Acylation of aroyl chlorides via a template Friedel–Crafts process: synthesis of indan-1,3-diones

Variously substituted indan-1,3-diones have been regioselectively prepared in a one-pot synthesis by sequential cross-condensation–cycloacylation of aromatic acyl chlorides and acetyl chloride or malonyl dichloride, electrophilic acylation of aromatic acyl chlorides representing the key step in the process. The synergism of the aromatic carbonyl enolization and the organization of the reacting system promoted by the metal is emphasized to account for the mild reaction conditions.