A Universal Platform for One-Pot Synthesis of Block Copolymers via Organoborane-Mediated Aerobic Tandem Polymerization

Block copolymers are pivotal to advanced materials, yet a general and operationally simple strategy for constructing diverse, well-defined block architectures from distinct monomer classes remains elusive. Here, we report an organoborane-mediated aerobic tandem polymerization system that seamlessly interlinks reversible addition-fragmentation chain-transfer (RAFT) polymerization with eight ring-opening (co)polymerization (RO(CO)P) techniques. This unified platform enables one-pot synthesis of an extensive array of block copolymers, including polyether-, polyester-, polypeptide-, CO₂-derived polycarbonate-, polyaziridine-, poly(ester thioester)-, and poly(ester amide)-<i>block</i>-polyacrylates. Mechanistic investigations demonstrate that strongly nucleophilic RO(CO)P active species (RX^-, X = O, N) react with an anhydride/thioanhydride to form less nucleophilic intermediates (RCOY^-, Y = O, S), which unlocks the controlled autoxidation of organoborane by O₂. This process generates alkyl radicals in situ and initiates a clean mechanistic switch from RO(CO)P to RAFT polymerization. Our work establishes a versatile and scalable route to previously inaccessible block copolymers while providing a general framework for unifying disparate polymerization mechanisms, opening broad avenues in polymer science and functional materials design.