Metal‐Free Deoxygenation and Reductive Disilylation of Nitroarenes by Organosilicon Reducing Reagents

A metal‐free deoxygenation and reductive disilylation of nitroarenes was achieved using N , N ′‐bis(trimethylsilyl)‐4,4′‐bipyridinylidene ( 1 ) under mild and neutral reaction conditions, and a broad functional group tolerance was possible in this reaction. Mono‐deoxygenation, giving a synthetically valuable N , O ‐bis(trimethylsilyl)phenylhydroxylamine ( 7 a ) as a readily available and safe phenylnitrene source from nitrobenzene, and double‐deoxygenation, giving N , N ‐bis(trimethylsilyl)anilines 8 , were easily controlled by varying the amounts of 1 and reaction temperature as well as adding dibenzothiophene (DBTP). Reaction of 2‐arylnitrobenzenes with 1 resulted in the formation of the corresponding carbazoles 14 via in situ‐generated phenylnitrene species derived by thermolysis of N , O ‐bis(trimethylsilyl)phenylhydroxylamines 7 , followed by their subsequent intramolecular C−H insertion. In addition, the intramolecular N−N coupling reaction proceeded in the reduction of 2,2′‐dinitrobiphenyl derivatives by 1 , giving the corresponding benzo[ c ]cinnolines.