Cyclic Seleninate Esters as Catalysts for the Oxidation of Sulfides to Sulfoxides, Epoxidation of Alkenes, and Conversion of Enamines to α-Hydroxyketones

Cyclic seleninate esters serve as catalysts for the rapid
oxidation
of sulfides to sulfoxides, alkenes to epoxides, and enamines to α-hydroxyketones.
Optimal conditions were found that minimize the overoxidation of the
product sulfoxides to sulfones and the hydrolysis of epoxides to diols.
In some examples such as styrene derivatives, oxidative cleavage was
observed instead of epoxidation. The enamine oxidations proceed via
the initial formation of dimeric 2,5-diamino-1,4-dioxane species,
which were hydrolyzed in situ to the final products.
The structure of one such dimer was confirmed by X-ray crystallography.