Thermal and photochemical racemization of chiral aromatic sulfoxides via the intermediacy of sulfoxide radical cations

Efficient racemization of enantiomerically pure methyl aryl sulfoxides was obtained by N-methylquinolinium tetrafluoborate (NMQ(+)) sensitized photolysis and by one-electron oxidation catalyzed by tris(2,2'-bipyridyl)ruthenium(III) hexafluorophosphate.