How can it be proved that (S)-bis-[2-(t-butylsulfinyl)phenyl] diselenide is a chiral non-racemic product?
Compounds with the general structure $\ce{R-SO-R'}$, i.e. containing a sulfinyl $\ce{-SO-{}}$ functional group attached to two carbon atoms, are called generically ‘sulfoxides’. Sulfoxides may be considered as a tetrahedral system composed of a central atom, ligands, and a lone pair of electrons (or phantom atom).



When the two organic residues $\ce{R}$ and $\ce{R'}$ are dissimilar, the sulfur atom is a stereogenic center.

The compound bis[2-(tert-butylsulfinyl)phenyl]diselenide contains two chiral sulfinyl groups and thus two stereogenic centers.



Therefore, three stereoisomers exist:


bis[2-((R)-tert-butylsulfinyl)phenyl]diselenide,  


bis[2-((S)-tert-butylsulfinyl)phenyl]diselenide,  


and the meso compound [2-((R)-tert-butylsulfinyl)phenyl][2-((S)-tert-butylsulfinyl)phenyl]diselenide