Reactivity of some butenolides towards intramolecular alkylation reactions

ABSTRACT

A furfurylidene -gamma- aryl delta- beta, Nu- butenolides Ib react with anhydrous aluminium chloride in the presence of toluene or anisole to give the same products obtained when benzene was used as a solvent, 4-arylbenzofuran-6-carboxylic acids III. The preferred intramolecular alkylation in case of Ib compared with the fluorenylidene analogues la, which under the same conditions undergo inter-molecular alkylation, is explained in terms of HMO calculations