Iron-Catalyzed Intermolecular N-H Insertion Using Acceptor-Acceptor Carbenes Derived from Iodonium Ylides

In this study, we report a general and efficient method for iron-catalyzed intermolecular N-H insertion at the intercarbonylic position of malonate reagents. Using iodonium ylides and simple iron(II) triflate as the catalyst, the reaction enables the functionalization of a wide range of primary and secondary aromatic and aliphatic amines in excellent yields. The reaction operates under exceptionally mild conditions, without the need for an inert atmosphere or anhydrous solvents, and proceeds in remarkably short reaction times. Mechanistic studies support a nonradical pathway in which an iron(II)-stabilized intermediate having hybrid carbene/carbocationic character undergoes nucleophilic attack by the amine.