Diversity‐Oriented Post‐Polymerization Modifications by Developing <i>gem</i> ‐Diboryl Polyolefin as a Platform Polymer

Post-polymerization modification (PPM) serves as a pivotal synthetic strategy for generating libraries of functional polymers from commodity precursors. The pursuit of practical and efficient PPM methods remains a longstanding objective in polymer chemistry. Herein, we report a novel diversity-oriented post-polymerization modification (DOPPM) protocol utilizing gem-diboryl polyolefin as a platform polymer. This polymer is readily synthesized via radical ring-opening polymerization of a gem-diboryl-substituted vinylcyclo-propane monomer. Density functional theory calculations reveal that the diboryl moiety effectively stabilizes the ring-opened propagating radical intermediate during polymerization, thereby promoting linear chain growth while suppressing competing 4-endo-trig cyclization that would lead to cyclic polymer formation. The gem-diboryl polyolefin exhibits exceptional reactivity and versatility in DOPPM, enabling its conversion into a wide range of functional polyolefins inaccessible via existing methods.