A Visible‐Light‐Driven, Metal‐free Route to Aromatic Amides via Radical Arylation of Isonitriles

Abstract

The photochemical metal-free carboamidation of aryl radicals has been exploited for the preparation of aromatic amides, including heteroand polyaromatic derivatives, under visible light irradiation of arylazo sulfones in the presence of isocyanides in aqueous acetonitrile. The process was useful for the smooth preparation of the antidepressant moclobemide.

Flow Photochemistry of Azosulfones: Application of “Sunflow” Reactors

“…Purification by flash chromatography (hexane: ethyl acetate 100 % hexane to 25 %) afforded 20 mg of 4 c (pale yellow solid, 40 %). The spectroscopic data of 4 c were in accordance with the literature [8]. 4-Bromo-N-(tert-butyl) benzamide (4 d).…”

“…The spectroscopic data of 4 a were in accordance with the literature. [8] N-(tert-Butyl)-4-cyanobenzamide ( 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57…”

“…Upon sunlight exposition both species are generated (Scheme ), and in the presence of suitable olefins and (hetero) arenes able to trap both species, the formation of a new aryl‐carbon bond took place efficiently. Such behavior has been exploited in the development of different photocatalyst‐free arylation protocols, for the preparation of allyl arenes, (hetero) biaryls, as well as aromatic amides …”

“…Such behavior has been exploited in the development of different photocatalyst-free arylation protocols, for the preparation of allyl arenes, [6] (hetero) biaryls, [7] as well as aromatic amides. [8]…”

“…The same reaction afforded 4 d in 33 % yield when using 10 equiv. of tertbutyl isonitrile [8]. N,4-Di-tert-butylbenzamide (4 e).…”