Aminooxylation Horner-Wadsworth-Emmons Sequence for the Synthesis of Enantioenriched γ-Functionalized Vinyl Sulfones.

An operationally simple protocol for the synthesis of γ-hydroxy vinyl sulfones has been developed using a proline-based aldehyde aminooxylation, followed by a vinyl sulfone forming Horner-Wadsworth-Emmons olefination. The adducts, formed in high enantiopurity, were subsequently converted to γ-azido vinyl sulfones, and azide-alkyne click chemistry enabled the synthesis of vinyl sulfone-based triazoles as potential nonpeptidic cysteine protease inhibitors.