Visible-Light-Promoted Radical Cascade Cyclization of 2-Vinyl Benzimidazoles: Access to Benzo[4,5]imidazo[1,2-]isoquinolin- 11(6)-ones.

A visible-light-enabled photoredox radical cascade cyclization of 2-vinyl benzimidazole derivatives is developed. This chemistry is applicable to a wide range of -aroyl 2-vinyl benzimidazoles as acceptors, and halo compounds, including alkyl halides, acyl chlorides and sulfonyl chlorides, as radical precursors. The Langlois reagent also serves as an effective partner in this photocatalytic oxidative cascade process.

Diazotization-Enabled Deaminative Late-Stage Functionalization of Primary Sulfonamides.

We, for the first time, disclosed a simple and efficient strategy for the late-stage functionalization of primary sulfonamides by diazotization, leading to sulfonyl chlorides, sulfonates, and complex sulfonamides. This protocol obviates the requirement for the prefunctionalization of sulfonamides. Its applicability is exemplified by the late-stage functionalization of sulfonamide-type drugs.