PEGylated Precision Segments Based on Sequence-Defined Thiolactone Oligomers.

A straightforward access route to multifunctional block copolymers, combining a poly(ethylene glycol) (PEG) block and a monodisperse segment with discrete monomer sequence based on thiolactone chemistry, is described. Exploiting an inverse conjugation strategy on a PEG preloaded poly(styrene) synthesis resin enables the convenient introduction of a predefined PEG-block at the α-terminus of thiolactone-based sequence-defined oligomers. Reaction conditions for the stepwise, submonomer synthesis at polar solid supports are optimized, using sequential synthesis on a model resin that enables to isolate and determine the purity of the oligomer segments by liquid chromatography-electrospray ionization mass spectrometry analysis. The reaction conditions are used to synthesize PEGylated 5mer precision polymers with defined monomer sequence in good yields and high purity to offer an interesting platform of macromolecules with potential for biomedical applications.