Hypervalent iodine(III)-induced intramolecular cyclization of α-(aryl)alkyl-β-dicarbonyl compounds:: A convenient synthesis of benzannulated and spirobenzannulated compounds

A novel hypervalent iodine(III)-induced direct intramolecular cyclization of alpha-(aryl)alkyl-beta -dicarbonyl compounds has been described. Both meta-and para-substituted phenol ether derivatives containing acyclic or cyclic 1,3-dicarbonyl moieties at the side chain undergo this reaction in a facile manner. The reactions afford benzannulated and spirobenzannulated compounds that are of biological importance. The reaction is found to be general, mild,: and high yielding. The mechanism: of the reaction has been shown to involve a cation radical intermediate.