The synthesis and ring-opening metathesis polymerization of glycomonomers

Abstract

The synthesis of a series of short poly(norbornene)s displaying pendant disaccharides is reported. para-(Propargyloxy)benzyl moieties were attached to a norbornenyl group via an ester or amide linkage, giving two different pre-monomers. A set of protected β-(1→6)-linked glucosamine-based disaccharides, structurally similar to the bacterial biofilm constituent poly-N-acetylglucosamine (PNAG), were attached to the pre-monomers via a Huisgen 1,3-dipolar cycloaddition reaction to generate a series of ‘glycomonomers’. In the presence of a Grubbs' 3^rd generation catalyst, the glycomonomers displayed variable reactivities that were dependent on the type of linkage (ester or amide) between the norbornenyl and benzyl moieties. In general, the amide-linked glycomonomers polymerized at a much slower rate and had a comparatively lower degree of polymerization than the corresponding ester-linked constructs. All the materials displayed a relatively narrow molecular weight distribution (Đ = 1.2–1.5).