Visible Light Promoted Iron-catalyzed Decarboxylative Alkylation

The lifetimes of iron complexes in the photoexcited states are much shorter than those of iridium and ruthenium complexes.Thus,the reactions catalyzed by iron complex with visible light are rare in organic synthesis.It is of great significance to promote the decarboxylation of carboxylic acids to generate alkyl free radicals by inexpensive iron salt and to fulfill the alkylation of heteroarenes.In this dissertation,the iron-substrate complexes have been used for intramolecular charge transfer process,and the iron-catalyzed decarboxylation alkylation of heteroarenes has been successfully achieved under visible light irradiation.It is worth noting that pyridine carboxylic acid as a ligand plays a key role in the reaction.The starting materials are cheap and commercially available,the reaction conditions are simple and mild,and the yields are modetate to excellent.The substrate scopes are abroad with respect to both heteroarenes and carboxylic acids.After preliminary mechanism research(radical trapping experiments,light on and off experiments,and ultraviolet-visible spectroscopy),we proposed the possible mechanism of the reaction.This reaction can quickly afford the high-value-added products from cheap commercial chemicals,and opened a new avenue for the visible light-promoted iron-catalyzed reactions.