Photoinduced sulfonylation of cyclic ethers

Sulfonylation of Benzylic C−H Bonds through the Reaction of Aryl(o‐tolyl)methanones with Sulfonyl Hydrazides or Sulfonyl Chlorides

“…Moreover, in addition to sulfonohydrazides, arylsulfonyl chlorides were also used in the sulfonylation of benzylic C−H bonds (Scheme ). It is known that arylsulfonyl radicals can be generated by the homolysis of arylsulfonyl chlorides through a SET process with excited ketones under UV irradiation in 1,4‐dioxane . Thus, we performed the reaction of phenyl( o ‐tolyl)methanone ( 1 a ) with 4‐methylbenzenesulfonyl chloride ( 4 a ) under UV irradiation.…”

“…For decades, photochemistry has been utilized as a powerful tool for the functionalization of C−H bonds with good chemoselectivity and regioselectivity . Aldehydes and ketones are widely used as photosensors in photochemical reactions, owing to their ability to absorb photons under illumination in certain regions of the electromagnetic spectrum . Another straightforward method has involved employing those small molecules as photocatalysts, as well as reactants .…”

Exploration of Dimethylzinc‐Mediated Radical Reactions

“…Compared to the time when we began this study, the methodology of C-H activation with radicals is now a surprisingly hot field of research. [93,94] From the viewpoint of regioselectivity, however, the current technologies still have some limitations. The intramolecular hydrogen-transfer process, discussed in the last section, would provide a powerful solution for this problem.…”

Dual Benzophenone/Copper‐Photocatalyzed Giese‐Type Alkylation of C(sp3)−H Bonds

“…[10] We also merged the photoreactivity of benzophenone with that of copper(II) complexes to develop photoreducible copper(II) precatalysts for applicationi n copper-catalyzed azide alkyne cycloadditiono rt he trifluoromethylationo fu nactivated terminal alkenes. [11] Based on these studies and previousliterature examples, in particular the seminal work of Inoue, Kamijo,and co-workersonthe functionalization of C(sp 3 )ÀHb onds photocatalyzed by aromatic ketones, [12] we hypothesized that combining the photoreactivity of BP with that of copper could be helpful to limit the polymerization in Giese-typereactions, as the alkyl radical intermediates I and II (Scheme1)m ight react with Cu II to generate masked radicals, [13] while low-valent Cu I/0 speciesp hotogenerated in situ might reduce II. [8c] We report herein that the combined use of catalytic amounts of BP andCu(OAc) 2 under mild UVAirradiationa llows isolation of the Giese reaction products in moderate to good yields from ar ange of donors, including trialkylamines,a nd highly polymerizable acceptorss uch as ethyl acrylate,a crylonitrile, and methyl vinyl ketone.…”