A Novel One-Pot Procedure for the Fast and Efficient Conversion of RAFT Polymers into Hydroxy-Functional Polymers

We report on the successful quantitative transformation of methacrylate and acrylate-type polymers prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization carrying a dithioester-end-group into hydroxy-functional polymers. The simple reaction procedure involves stirring a solution of the dithioester-capped polymer and an azo-initiator in tetrahydrofuran at elevated temperatures (T = 60 degrees C) in the presence of air. This reaction quantitatively yields hydroperoxide functionalities that can be efficiently reduced to hydroxy groups in a one-pot procedure using triphenylphosphine. Size exclusion chromatography-electrospray mass spectrometry was employed to monitor the progress of the reaction. The new backbone-linked hydroxy group provides a versatile anchor for chemical end-group conversions and conjugation reactions with prepared RAFT polymers, which alleviates problems with the rather limited ability of the dithioester-end-group to undergo non-radical transformations.