Dibenzofurans, carbazoles, fluorenones and phenanthridones prepn. - by reacting diphenyl ethers, diphenylamines, benzophenones and benzanilides with palladium (II) salts

摘要

Opt. substd. dibenzofurans, carbazoles, 9-fluorenones or 6-phenanthridones are prepd. by reacting the corresp. diphenyl ethers, diphenylamines, benzophenones or benzanilides with Pd (II) salts in a polar solvent (pref. acetic acid, trifluoroacetic acid, acetonitrile or sulpholane), advantageously in the presence of catalytic amounts of strong acids or BF3. The products are predominantly known cpds. useful e.g. as inters. for pharmaceuticals. The known cyclization of diphenyl ether with Pd acetate to dibenzofuran, when carried out in the presence of a strongly polar solvent is practically quantitative.