Oxidative fluorination in the Ph2SO-XeF2-Cl− system and fluorine exchange in the Ph2S(O)F2-Ph2S(O)F+ system

Oxidative fluorination of diphenyl sulfoxide with xenon difluoride occurs under mild conditions in the presence of chloride ion to give Ph 2 S(O)F 2 in quantitative yield. Chloride ion appears to react with xenon difluoride to generate fluoride ion, and a mechanism of oxidative fluorination is proposed that involves anionic Ph 2 S(O)F − and radical Ph 2 S(O)F * intermediates. Addition of cationic Ph 2 S(O)F + to Ph 2 S(O)F 2 initiates rapid fluorine exchange, presumably via a symmetrical fluorine-bridged intermediate, and this exchange process was monitored by 13 C and 19 F NMR spectroscopy. In the presence of chloride ion, Ph 2 S(O)Cl 2 is formed and can be identified by 13 C NMR and by its hydrolysis to Ph 2 SO 2 . Mechanisms are proposed for these reactions, and ab initio molecular orbital calculations ( GAUSSIAN 92) were carried out of the postulated intermediates. Key words: preparation of Ph 2 S(O)F 2 , Ph 2 S(O)F + , and Ph 2 S(O)Cl 2 ; oxidative fluorination in the Ph 2 SO-XeF 2 -Cl − system; fluorine exchange in the Ph 2 S(O)F 2 -Ph 2 S(O)F + system.