Activated Polyacrylamides as Versatile Substrates for Postpolymerization Modification

The
displacement of an activated leaving group in polymeric repeat
units is a powerful method of postpolymerization modification. This
strategy enables
the synthesis of polymers otherwise unobtainable by direct polymerization
as well as the preparation of a diverse array of macromolecular structures.
We demonstrate that the activation of acrylamide through the introduction
of two tert-butyloxycarbamate (Boc) groups followed
by radical polymerization leads to a new class of activated polyacrylamides
analogous to well-known activated polyacrylates. Transamidation of
poly­(di­(Boc)-acrylamide) utilizing primary amines proceeds to high
conversion under mild conditions, and the products can be readily
purified. Less nucleophilic secondary amines and alcohols require
more forcing conditions. We demonstrate the utility of this approach
by preparing copolymers capable of on-demand gel formation and the
synthesis of block polymers using controlled radical polymerization.