Synthesis of 1,2-disubstituted benzimidazoles using an aza-Wittig-equivalent process
作者:Yuan Chen、Fanghui Xu、Zhihua Sun
DOI:10.1039/c7ra09010b
日期:——
A synthetic approach for 1,2-disubstituted benzimidazoles has been successfully designed based on effective C–N bond construction, which demonstrated mild reaction conditions and excellent yields. The method involves treating derivatives of o-phenylenediamine with tert-butanesulfoxide and NBS under acidic conditions, which undergoes an aza-Wittig-equivalent process to afford the desired products. Using
Palladium-catalyzed N-heteroannulation of N-allyl- or N-benzyl-2-nitrobenzenamines: synthesis of 2-substituted benzimidazoles
作者:Jeremiah W. Hubbard、Adam M. Piegols、Björn C.G. Söderberg
DOI:10.1016/j.tet.2007.05.010
日期:2007.7
A palladium-catalyzed reductive N-heteroannulation of N-allyl- or N-benzyl-2-nitrobenzenamines, using carbon monoxide as the ultimate reducing agent, affording 2-substituted benzimidazoles has been developed.
Copper Catalyzed N-Arylation of Amidines with Aryl Boronic Acids and One-Pot Synthesis of Benzimidazoles by a Chan–Lam–Evans N-Arylation and C–H Activation/C–N Bond Forming Process
Mono-N-arylation of benzamidines 1 with aryl boronic acids 2 was effectively achieved in the presence of a catalytic amount of Cu(OAc)(2) and NaOPiv under mild aerobic conditions. Combining this step with an intramolecular direct C-H bond functionalization, catalyzed by the same catalytic system but under oxygen at 120 degrees C, afforded benzimidazoles 3 in good to excellent yields.