The First Direct Oxidative Conversion of a Selenol to a Stable Selenenic Acid:  Experimental Demonstration of Three Processes Included in the Catalytic Cycle of Glutathione Peroxidase

[structure: see text]. A stable selenenic acid was synthesized by direct oxidation of a selenol bearing a novel bowl-type substituent with H2O2, and its structure was established by X-ray crystallographic analysis. Selenenyl sulfides obtained by the reaction of the selenenic acid with 1,4-dithiols were reduced to the corresponding selenol by treatment with a tertiary amine, thus achieving the experimental demonstration of three processes included in the catalytic cycle of glutathione peroxidase.