Nucleophilic substitution in O-phenyldibenzofuranium and 10-phenylxanthonium cations

Article abstract of DOI:10.1007/BF02495215

Reactions of O-phenyldibenzofuranium tetrafluoroborate with nucleophiles (OH^-, NO₂^-, AcO^-) in aqueous media follow the S_NAr-mechanism and involve dehydroarenes. In DMSO, this salt smoothly reacts with NO₂^- and I^- with predominant opening of the furan ring. 10-Phenylxanthonium tetrafluoroborate readily arylates the NO₂^- ion in water (at the N and O atoms), mainly with predominant opening of the central ring, and is completely decomposed even with weak bases (NH₂OH, 2,4-dinitrophenylhydrazine). The Baeyer -Villiger oxidation of this salt affords xanthone and 2-phenoxybenzoic acid.