A Naphthyl-Containing Alkoxyamine Initiator Enabling Controlled Methacrylate Polymerization Under Mild Conditions

Nitroxide-mediated polymerization (NMP) is a powerful technique, yet achieving precise control over methacrylic esters remains challenging. A novel alkoxyamine initiator, 3-(((2-cyanopropan-2-yl)oxy)(cyclohexyl)amino)-2,2-dimethyl-3-naphthylpropanenitrile (CNDN), featuring bulky naphthyl group, was synthesized via a three-step route (Schiff base reduction, Oxone oxidation, and radical coupling). This alkoxyamine enables well-controlled polymerization of methyl methacrylate (MMA) at 80°C with dispersities below 1.45. The polymerization follows first-order kinetics, and the molecular weight increases linearly with conversion. The high steric hindrance suppresses bimolecular termination, ensuring excellent end-group fidelity and successful chain extension with MMA, ethyl methacrylate, and styrene. Notably, CNDN also mediates controlled MMA polymerization without deoxygenation. This work presents an efficient initiator for controlled methacrylate polymerization under mild conditions and introduces a novel synthetic strategy that could enable general access to structurally diverse alkoxyamines. The resulting naphthyl-terminated polymers hold promise for fluorescent labeling, optical materials, and nanoparticle dispersants. Graphical A naphthyl-containing alkoxyamine initiator (CNDN) enables controlled methacrylate polymerization at 80°C with low dispersity, even without deoxygenation. This novel synthesis strategy could offer a versatile platform for accessing structurally diverse alkoxyamines for precision polymer materials.