Visible light-driven azidation of vinyl arenes with azidobenziodoxole as the azidating agent was investigated in acetonitrile by using Cu­(I)­(phenanthroline)2 complex [Cu­(dap)2]­PF6 as photocatalyst. The reactions generated three types of difunctionalization products, which correspond to reaction patterns of amido-azidation, benzoyloxy-azidation, and diazidation. The electronic nature of the aryl group attached to the olefin moiety was found to play a crucial role in determining the reaction consequence: when the aryl group was electron-rich, the reactions afforded benzoyloxy-azidation products exclusively; for highly electron-deficient vinyl arenes, by contrast, diazidation products were generated in moderate yields. When the aryl group was moderately electron-rich or electron-deficient, on the other hand, a three-component reaction involving acetonitrile as well as azidobenziodoxole took place to give predominantly amido-azidation products. A plausible mechanism is proposed based on the mechanistic studies to rationalize these results. The reactions of electronically less biased vinyl arenes probably proceed via a redox catalysis pathway, while the electron-rich alkenes are believed to be converted through a radical chain process. The present reactions may be of synthetic usefulness as they provide a new means for the amido-azidation of vinyl arenes.

The C­(sp3)–H functionalization of O-pentafluorobenzoyl ketone oximes was implemented under visible light irradiation with copper complexes as catalysts. The reactions involve iminyl-radical-mediated intramolecular hydrogen atom transfer as the key step, with the iminyl radicals being generated via copper-effected N–O cleavage. The reaction afforded 3,4-dihydro-2H-pyrroles under the conditions of [Cu­(DPEphos)­(bcp)]­PF6 and DABCO, while γ-pentafluoro­benzoyloxy ketones were produced predominantly when [Cu­(dpp)2]­PF6 and InCl3·4H2O were used as catalysts.

The C(sp 3)À H chlorination of aliphatic sulfonamides was realized by visible-light photoredox catalysis with Ru (bpy) 3 Cl 2 as photocatalsyt and NaOCl•5H 2 O crystals as the chlorinating agent. The reaction proceeds in a tandem pattern of NÀ H chlorination and Hofmann-Löffler-Freytag

A domino sulfonylation/intramolecular C–N coupling/dehydrogenation reaction was realized between pent-4-ynamides and sulfonyl chlorides by catalysis of Cu­(acac)2 and 2,2′-bis­(diphenylphosphanyl)-1,1′-binaphthalene. The reaction provides a convenient approach to sulfonyl-functionalized pyrrol-2-ones. This method can also be applied to the synthesis of 3-alkylidene isoindolinones from 2-ethynyl-benzamides.