A new transformation of coumarins via direct C–H bond activation utilizing an iron–organic framework as a recyclable catalyst†
A new mixed-linker iron-based MOF VNU-20 [Fe3(BTC)(NDC)2·6.65H2O] was solvothermally synthesized from 1,3,5-benzenetricarboxylic acid, 2,6-naphthalenedicarboxylic acid and FeCl2. VNU-20 was utilized as a recyclable catalyst for the functionalization of coumarins with N,N-dimethylanilines via direct C–H bond activation. This Fe-MOF was found to be more active towards the coupling transformation than several conventional homogeneous and MOF-based heterogeneous catalysts. To the best of our knowledge, this is the first time that [Fe3(CO2)7]∞ SBUs are evaluated for their catalytic activity, and this transformation of coumarins is new.