Phenanthroline-based metal–organic frameworks for Fe-catalyzed Csp3–H amination

Abstract

We report here the synthesis of a robust and highly porous Fe-phenanthroline-based metal–organic framework (MOF) and its application in catalyzing challenging inter- and intramolecular C–H amination reactions. For the intermolecular amination reactions, a FeBr₂-metalated MOF selectively functionalized secondary benzylic and allylic C–H bonds. The intramolecular amination reactions utilizing organic azides as the nitrene source required the reduction of the FeBr₂-metalated MOF with NaBHEt₃ to generate the active catalyst. For both reactions, Fe or Zr leaching was less than 0.1%, and MOFs could be recycled and reused with no loss in catalytic activity. Furthermore, MOF catalysts were significantly more active than the corresponding homogeneous analogs. This work demonstrates the great potential of MOFs in generating highly active, recyclable, and reusable earth abundant metal catalysts for challenging organic transformations.