Diverse Functionalization of Nonpolar Polyolefins through Late-Stage Incorporation of Alkyl Bromides

The late-stage diversification of nonpolar polyolefins remains a longstanding challenge due to the chemical inertness of their C–H bonds and the limited functional group incorporation of existing modification strategies. Herein, we report a general and versatile approach for the diverse functionalization of polyethylene and polypropylene through the late-stage installation of primary alkyl bromides. Using a rhodium-catalyzed C–H carbene insertion reaction, chemically inert polyolefins are efficiently transformed into alkyl bromide-bearing polymers under mild conditions. The resulting primary alkyl bromides serve as robust and highly reactive platforms for subsequent nucleophilic substitution (SN2) reactions, while the tertiary bromides are highly beneficial for subsequent atom transfer radical polymerization (ATRP). This strategy enables the fast introduction of a broad range of functional groups, such as ester, amine, azide, iodine, thiocyanate, thiol, etc., from a single common intermediate, offering a unified and modular pathway to access diverse functional polyolefins. The synthesis of fluorescent polymers and the mechanical recycling of mixed plastics were further demonstrated as potential applications. We anticipate that this leaving-group-enabled late-stage diversification strategy will significantly expand the chemical space of nonpolar polyolefins and accelerate the discovery of functional polymer materials.