Selective transformation of propargylic ester towards tunable polymerization pathways

Divergent synthesis of numerous complex molecules has emerged as a promising strategy as it allows the access to structurally distinct products from identical starting materials. However, selective transformation of the same monomer into diverse polymers by modulating the polymerization conditions remains a synthetic challenge. In this work, we report the design of propargylic ester, which can be selectively transformed into polyimidate, polyimine, or polyamidine through distinct polymerization pathways. By modulating polymerization conditions, either ester migrating or ester leaving can be selectively manipulated with the formation of different nitrogen-containing intermediates including imine, ketenimine, and alkylidene ketenimine. Three types of polymers could be exclusively obtained using one set of monomer combination containing propargylic ester and sulfonyl azide. In this work, the tunable ester leaving or migrating ability for propargylic ester allows it as a variable synthon monomer, which can facilitate varied transformations towards structure-diverse polymers.