Photoredox-catalyzed synthesis of sulfonated oxazolines from N-allylamides through the insertion of sulfur dioxide

Abstract

Photoredox-catalyzed generation of sulfonated oxazolines starting from N-allylamides, DABCO·(SO₂)₂, and aryldiazonium salts has been developed. A range of sulfonated oxazolines were obtained in moderate to good yields. This transformation involves the sequential insertion of sulfur dioxide, intermolecular sulfonylation of alkenes and intramolecular cyclization via a radical process. This protocol features good compatibility of functional groups and mild reaction conditions. Sulfonated oxazolines could be efficiently transformed into β-amino alcohol, which is an important moiety in pharmaceuticals.