Regiodivergent Chain-Growth Polymerization of Aza-π-Allylpalladium Zwitterions via Proton Transfer

Proton transfer is a fundamental process in many ring-opening polymerization (ROP) strategies, imparting precise control over polymer chain growth under mild conditions. Merging proton transfer mechanism with versatile reactive intermediates-such as organometallic species-presents exciting opportunities to unlock new chemical space for polymer synthesis. Here, we report a mild palladium-catalyzed ROP of N-sulfonyl vinyl aziridines via a π-allyl-Pd^II-N^- zwitterionic intermediate. This polymerization features unique initiation and propagation proceeding through 1) proton transfer from a diversity of protic X─H/C─H bonds, and 2) subsequent ligand-controlled regiodivergent allylic amination reaction. This approach enables the synthesis of a range of nitrogen-containing homo- and copolymers, surpassing traditional base-promoted polymerization methods by expanding the amine spacing and enhancing functional group tolerance.