N-Heterocyclic Carbene Promoted Construction of Amide-Linked COFs via the Oxidation of Imine-Linked COFs with Molecular Oxygen

While amide-linked covalent organic frameworks (COFs) have gained significant research attention due to their stability, there is currently no universal method for creating amide-linked COFs with diverse chemical structures. Here, we present a gentle, precise, and versatile synthetic approach to amide-linked COFs using N-heterocyclic carbene (NHC)-mediated oxidation with molecular oxygen as the oxidant. This approach is gentle and selective, and even fragile functional groups like thioethers are able to survive the transformation. Additionally, this method does not require dangerous conditions such as high pressure or strong oxidants, making it a promising way to create functional amide-linked COFs.