Copper‐Promoted Thiolation of C(sp²)–H Bonds Using a 2‐Amino Alkylbenzimidazole Directing Group

Abstract

A copper‐promoted thiolation of C(sp2)–H bonds with disulfides was achieved by using 2‐amino alkylbenzimidazole (MBIP amine) as a new and removable N,N‐bidentate directing group. This strategy gives a variety of functionalized thioethers in moderate to excellent yields in a simple and efficient way. Importantly, the substrate scope is not limited to aromatic amides; diverse alkenyl amides are also compatible. Furthermore, this synthetic approach provides a potentially feasible way to achieve structural modification of related benzimidazole‐containing compounds through direct C–H activation.

Carboxylate-Directed Addition of Aromatic C–H Bond to Aromatic Aldehydes under Ruthenium Catalysis

“…1n-d5 was prepared from bromobenzene-d 5 according to the reported literature. 43 4.2. Preparation of 3PCy 3 -Ru/CeO 2 Catalyst.…”

“…The product was heated in a box furnace at a rate of 10 °C min –1 and maintained at 400 °C for 30 min to afford ceria in an excellent ceramic yield. 1n- d5 was prepared from bromobenzene- d 5 according to the reported literature …”

3d Transition Metals for C–H Activation

“…In subsequent contributions, the synthetic scope of copper-catalyzed C−H chalogenation was significantly elaborated to use alkyl and aryl thiols, 1862,1863 thiosugars, 1864 disulfides, 1865 and diselenides 1866 as the coupling partners. In this case of the auxiliary 2-(pyridin-2-yl)isopropyl-amine (PIP-amine; Scheme 764c), 1867 and the 2-amino alkylbenzimidazole (MBIP amine; Scheme 764d) 1868 bidentate DG were employed in the ortho-selective C−H chalcogenation of amides.…”

Recent advances in selective mono-/dichalcogenation and exclusive dichalcogenation of C(sp2)–H and C(sp3)–H bonds

“…Although the transition metal-catalyzed chelation-assisted C(sp 2 )–H chalcogenation has been reviewed in several elegant works, 58,66,68 most of them are concerned about the monochalcogenation and only sporadic examples of dichalcogenation have been discussed. 112–130 Generally, the outcomes of mono-/dichalcogenation are determined by the intrinsic electronic and steric properties of substrates. However, selective mono-/dichalcogenation could be achieved by controlling the reagent loadings, the types of solvents/bases, and a combination of various factors.…”