Unusual asymmetric oxidation of sulfide; the diastereoselective oxidation of prochiral sulfide-chiral acid salt with hydrogen peroxide without metal

The sulfide was treated with chiral acid in a mixture of toluene and methyl iso-butylketone to precipitate the salt, which reacted with 30% H2O2 for 3 weeks at rt. The resulting crystals were collected followed by recrystallization to give the salt of enantiometrically pure sulfoxide and chiral acid in 72% yield and 98.1% de, which was led to chiral sulfoxide after neutralization. Sulfoxide was led to as the candidate for an orally active HIV-1 therapeutic agent.