含羧基共价有机骨架的合成及其在钌催化邻位苄基 化反应中的应用

Imine-based covalent organic frameworks (COFs) with different functional groups have brought great application potentials in many fields, including heterogeneous catalysis. Herein, we report the synthesis of COFs containing carboxylic acid groups and their first application in the ruthenium-catalyzed synthesis of diarylmethane derivatives. Two new carboxyl-containing COFs (Tp-DAT and DHTA-DAT) have been prepared from 2,5-diaminoterephthalic acid and benzene-1,3,5-tricarbaldehyde derivatives with different numbers of hydroxy groups. Both Tp-DAT and DHTA-DAT COFs show high activity in the ruthenium-catalyzed ortho-C–H benzylation of 2-arylpyridines. Tp-DAT COF, which is fully linked by β-ketoenamine, has high stability, good yields and high chemoselectivity for ortho-benzylation and thus exhibits advantages in heterogeneous catalytic reactions.