Metal-free C–Se cross-coupling enabled by photoinduced inter-molecular charge transfer

Abstract

Metal-free C-Se cross-couplings via the formation of electron-donor-acceptor (EDA) complexes have been developed. The visible-light induced reactions can be applied for the synthesis of a series of unsymmetrical diaryl selenides...

Visible-light-driven photoredox-catalyzed C(sp3)–C(sp3) cross-coupling ofN-arylamines with cycloketone oxime esters

“…Visible light photocatalysis has been developed as a powerful tool for organic transformation due to its environmental friendliness and sustainability, 4,5 and recently applied in alkylation of N -arylamines. 6 In 2017, Yu and co-workers reported a novel visible-light-driven palladium-catalyzed radical alkylation of N -arylamines with alkyl bromides; various tertiary, secondary, and primary unactivated alkyl bromides undergo this simple reaction for the construction of quaternary centers (Scheme 1a).…”

Visible-light-driven C(sp2)–H arylation of phenols with arylbromides enabled by electron donor–acceptor excitation

“…15 For example, EDA complexes derived from aryl halides as electron-accepting substrates and thiolate anions or selenolate anions as electron donors undergo photoinduced C(sp 2 )–S/Se cross-coupling under catalyst-free conditions. 16 Inspired by these reports, we speculated that electron-rich phenolates might form EDA complexes with aryl halides. The reactions did not form C–O cross-coupling products but produced 2-arylated phenols under blue LED irradiation at ambient temperature.…”

Recent Advances in Light-Induced Selenylation

“…Intermolecular charge transfer occurring upon visible light exposure generates, along with a halide anion, the selenyl/aryl radical pair, and the desired product 5.3 was then obtained by radical−radical coupling (Scheme 5). 43 A related reaction has been reported for the UV light mediated coupling of aryl halides (iodides and bromide) with diselenides in argon saturated acetonitrile, in the presence of DBU. A 300 W Hg lamp was adopted as the light source, and, again, a selenyl radical was suggested as the intermediate.…”

“…Intermolecular charge transfer occurring upon visible light exposure generates, along with a halide anion, the selenyl/aryl radical pair, and the desired product 5.3 was then obtained by radical–radical coupling ( Scheme 5 ). 43 …”