Visible-Light-Enabled Sulfonyl Radical-Triggered Cyclization Strategy for the Efficient Synthesis of Benzosultams

We introduce a green and practical
visible-light-driven
method
to synthesize benzosultam derivatives using an eosin Y organophotocatalyst.
Under ambient conditions, N-alkyl-N-propargyl arylsulfonamides react with sodium aryl sulfinates through
a sulfonyl-radical-driven cyclization to produce the corresponding
exocyclic benzosultams.
Furthermore, these products smoothly isomerize to their endocyclic
forms with a mild base. This metal-free approach is mild, versatile,
and eco-friendly, providing excellent yields over a wide range of
substrates.