Synthesis of 2-arylbenzimidazoles via microwave Suzuki–Miyaura reaction of unprotected 2-chlorobenzimidazoles
作者:Brad M. Savall、Jill R. Fontimayor
DOI:10.1016/j.tetlet.2008.09.043
日期:2008.11
A series of 2-arylbenzimidazoles were synthesized via microwave-mediated Suzuki-Miyaura coupling of 2-chloro benzimidazoles and either arylboronic acids or aryltrifluoroborate salts. The most notable aspect of the present work is that there is no need for protection of the benzimidazoles. In addition, reaction conditions were optimized to reduce homo coupling of pyridylboronic acids. (C) 2008 Elsevier Ltd. All rights reserved.
Metal-free selective synthesis of 2-substituted benzimidazoles catalyzed by Brönsted acidic ionic liquid: Convenient access to one-pot synthesis of N-alkylated 1,2-disubstituted benzimidazoles
A novel efficient method for the selective synthesis of 2-substituted benzimidazoles is described through condensation reaction of o-phenylenediamines with a wide rang of aliphatic, aromatic and heteroaromatic aldehyde substrates using Brönsted acidic ionic liquid as a reusable catalyst under metal-free conditions at ambient temperature. Notably, Dodecylimidazolium hydrogen sulfate ([DodecIm][HSO4])
modification (PSM) facilitate charge carrier transfer and photogeneration ability of superoxide radicals (O2˙−), which makes these NQ-COFs more efficient photocatalysts for O2˙− mediated synthesis of 2-benzimidazole derivatives. The general applicability of this synthetic strategy is demonstrated by fabricating 12 other crystalline NQ-COFs with a diversity of topologies and functional groups.