ROMP copolymers for orthogonal click functionalizations

The ring opening metathesis polymerization using ruthenium carbene initiators developed by Grubbs et al. is one of the most functional group tolerant living polymerization methods known. One of the most used post-polymerization functionalization methods used today is the copper-catalyzed 1,3-dipolar cycloaddition between alkynes and organic azides. Organic azides are, however, not tolerated by ruthenium carbene initiators and non-protected alkynes have been shown to slow down the propagation reaction or react with the propagating species leading to broad molecular weight distributions. Here we report the copolymer synthesis of three orthogonally functionalizable monomers, one carrying an activated pentafluorophenyl ester, one a maleimide unit and a third one a trialkyl silyl protected alkyne. From these monomers, statistical terpolymers as well as diblock copolymers were synthesized with different molecular weights and monomer compositions or block ratios, respectively. Excellent control over molecular weight and molecular weight distribution could be achieved using Grubbs’ first generation ruthenium carbene initiator. Herein we present the synthesis and orthogonal triple post-polymerization functionalization of these copolymers.