Synthesis of End-Functionalized Poly(norbornenes) and Poly(ethylidene norbornenes) Using a Pd(II) Catalyst in Combination with Chain Transfer Agents

Synthesis of end-functionalized poly­(norbornenes) (PNBs) and poly­(ethylidenenorbornenes) (PENBs) were prepared using the palladium catalyst tBu3PPdMeCl/NaBArf in combination with the chain transfer agents (CTAs) 4-penten-1-ol and 10-undecenal. These CTAs produce polymers end-capped with −OH and −CHO groups, respectively, in high yields with Mn values in the range of 6–17K, depending on the CTA:monomer molar ratio. End-functionalized PNBs and PENBs with precisely controlled Mn values and very narrow molecular weight distributions were accessed by using 4-penten-1-ol and 10-undecenal as chain-terminating agents following living polymerizations in which the monomer is completely consumed. The utility of the aldehyde-functionalized polymers is illustrated via coupling to a dye molecule and by the synthesis of ambiphilic diblock copolymers, PNB-b-PEG and PENB-b-PEG.