The first example of visible-light-induced deoxygenative C2-sulfonylation of quinoline N-oxides with sulfinic acids in the presence of an organic dye as the catalyst was developed. The reaction conditions are eco-friendly and mild, employing ambient air as the sole oxidant and aqueous acetone solution as the solvent. This approach requires only a very low catalyst loading, allowing gram-scale preparation as well as late-stage modification of biologically active compounds bearing quinoline groups.

A mild and eco-friendly visible-light-induced decarboxylative acylation of quinoxalin-2(1H)-ones and α-oxo carboxylic acids with ambient air as the sole oxidant at room temperature was established. The reaction proceeded efficiently without any metal catalysts, strong oxidants or external-photosensitizers, ultimately reducing the generation of waste.

Without employing any base and organic solvent, an economical, practical and eco-friendly protocol has been developed for the ultrasound accelerated one-pot synthesis of various functionalized 2-sulfonylquinolines from easily accessible starting materials in water under open-air conditions.

The first example of a metal- and reductant-free deoxygenative sulfonylation of quinoline N-oxides with sodium sulfinates via a dual radical coupling process is reported. In this reaction, sodium sulfinates play dual roles of a sulfonylation reagent and activating agent. This procedure is expected to complement the current methods for the radical reaction of quinoline N-oxides.

Aryl radicals were generated for the first time from cheap and easily available aryl acyl peroxides in eco-friendly ethyl acetate under ambient conditions and visible-light illumination in the absence of any additive, metal catalyst, or external photosensitizer. The present arylation of quinoxalin-2(1H)-ones was chemo- and regioselective, and provided good access to various 3-arylquinoxalin-2(1H)-ones.