College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou, Henan Province 450001, People's Republic of China.
J Org Chem. 2017 Mar 17;82(6):3152-3158. doi: 10.1021/acs.joc.7b00142. Epub 2017 Mar 2.
A practical intramolecular C-H amidation methodology has been developed using molecular iodine under basic conditions. The required imine substrates were readily obtained by condensation of simple o-phenylenediamine derivatives and aldehydes. The transition-metal-free cyclization reaction described here works well with crude imines and allows for the sequential synthesis of N-protected benzimidazoles without purification of the less stable condensation intermediates. This operationally simple synthetic approach is broadly applicable to a variety of aromatic, aliphatic, and cinnamic aldehydes to produce diverse 1,2-disubstituted benzimidazole derivatives in an efficient and scalable fashion.
一种实用的分子内 C-H 酰胺化方法已经开发出来，使用的是碱性条件下的分子碘。所需的亚胺底物可以通过简单的邻苯二胺衍生物和醛的缩合反应很容易地得到。这里描述的无过渡金属环化反应对粗亚胺效果很好，并允许在不纯化不太稳定的缩合中间体的情况下连续合成 N-保护的苯并咪唑。这种操作简单的合成方法广泛适用于各种芳香族、脂肪族和肉桂醛，以高效和规模化的方式生产各种 1,2-取代的苯并咪唑衍生物。
