Amidyl Radical-Mediated Polyolefin C–H Functionalization

Polyolefins, polyaromatics, polyesters, and polyethers comprise 63% of plastics worldwide. Their utility in modern society has enabled advancements but consequently has also led to rapid plastic accumulation. Using these waste materials as reactants, recent developments in the field of C–H functionalization as a post-polymerization modification technique of the commodity polymers are discussed. Xanthylation of atactic poly(butene) was possible via the use of a N-xanthylamide reagent. The method was regioselective, chemoselective, and modular to establish this as a platform methodology for the functionalization of polyolefins using blue light irradiation. Hyperbranched polyethylene was thermally xanthylated, trithiocarbonylated, and dithiocarbamylated via an amidyl radical intermediate. The mechanism of C–H functionalization was deduced through kinetic and crossover experiments. The method was translated to semicrystalline polymers and ultimately to reacting within a twin-screw extruder, yielding 10 grams of xanthylated isotactic polypropylene. In this work, we report an approach to aliphatic C–H diversification via radical chain transfer featuring an easily prepared O–alkenylhydroxamate reagent, which upon mild heatingfacilitates a variety of valuable aliphatic C–H functionalizations. This method enabled the functionalization of a range of polyolefins via challenging and previously undeveloped C–H transformations. The simplicity and generality of this strategy constitute an ideal approach for the diversification of unactivated, aliphatic C–H bonds.Doctor of Philosoph