Iron-Catalyzed Site-Selective Bromination of Benzylic C(sp3)–H Bonds

An iron-catalyzed chemo- and site-selective benzylic C-H bromination has been described. The practical approach uses the C-H substrate as the limiting reagent and commercially available iron(II) bromide at a loading of 1 mol % as the catalyst without the involvement of any extrinsic ligand. The simple and mild reaction can be readily scaled up to gram quantity with good functional group tolerance, offering a convenient route for the late-stage diversification of complex bioactive natural products and pharmaceutical molecules through sequential benzylic C-H bromination.