Photocontrolled Radical Polymerization from Hydridic C–H Bonds
Given the ubiquity of C–H bonds in biomolecules and polymer backbones, the development of a photocontrolled polymerization from a C–H bond would represent a powerful strategy for selective polymer conjugation precluding several synthetic steps to introduce complex functionality. We have developed a hydrogen-atom abstraction strategy that allows for a controlled polymerization from a C–H bond using a benzophenone photocatalyst, a trithiocarbonate-derived disulfide, and visible light. We perform the polymerization from a variety of ethers, alkanes, unactivated C–H bonds, and alcohols as well as showcase the applicability of the method to several monomer classes. Our method lends itself to photocontrol which has important implications for building advanced macromolecular architectures. Finally, we demonstrate that we can graft polymer chains controllably from poly(ethylene glycol) showcasing the potential application of this method for controlled grafting from C–H bonds of commodity polymers.