Hydroalkylation Polymerization of Electron-Neutral/Rich Alkenes by Merging Photoredox Catalysis and Hydrogen Atom Transfer

Abstract

The development of efficient polymerization reactions to utilize abundant and inexpensive alkenes for the design of functional polymeric materials is of great significance. Herein, we report the first photocatalytic hydroalkylation polymerization of electron-neutral/rich alkenes with active methylene-containing acetoacetate monomers, enabled by the synergy of photoredox catalysis and hydrogen atom transfer. The rationally designed multifunctional 4CzIPN/(3-Me)PhSH/LiOtBu catalytic system exerts exceptional control over chemoselectivity and regioselectivity, favoring exclusive anti-Markovnikov mono-addition. Endowed with 100% atom economy, mild reaction conditions, broad monomer generality, high yields, and high molecular weight polymers (Mw up to 75.6 kDa), this versatile platform enables the synthesis of structurally diverse polymers from abundant alkene feedstocks—exemplified by oligo(ethylene glycol)-based thermoresponsive polymers with finely tunable LCST behavior and cloud point temperatures. Reactive methine units embedded in the polymer backbone enable versatile post-polymerization modification and multimode structural diversification, while facilitating the construction of chemically recyclable polymer networks via dynamic covalent cross-linking. This work introduces an innovative polymerization paradigm, opening new opportunities for the rational design of stimuli-responsive, functionally versatile, and circular polymeric materials.