Carbonylation of polyfluorinated indans, tetralins and perfluoro-2,3-dihydrobenzofuran under the action of CO/SbF₅

Polyfluorinated indans and tetralins are carbonylated under the action of CO/SbF₅ at room temperature and atmospheric pressure. Perfluoroindan and its 4-CF₃, 5-CF₃, 5-CH₃, 1,1-H,H derivatives add two CO molecules to form the corresponding dimethyl indan-1,1-dicarboxylates after methanolysis, and/or 1-hydroindan-1-carboxylic acids after hydrolysis. 1-X-Perfluoroindans (X[dbnd]CF₃, C₂F₅, C₆F₅, H) and 1-X-perfluorotetralins (X[dbnd]C₂F₅, C₆F₅) add one CO molecule at the 1-position to give the corresponding 1-carbonyl fluorides. Reaction of the latter with methanol gives methyl esters, whereas hydrolysis is accompanied by decarboxylation. Perfluoro-2,3-dihydrobenzofuran under the action of CO/SbF₅ gives both mono- and dicarbonylation products.