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.