Synthesis and post-polymerization modification of poly(propargyl 2-ylidene-acetate)

Rhodium(I)-catalyzed C1 polymerization of propargyl 2-diazoacetate was conducted for the first time resulting in a novel functional polymethylene derivative, poly(propargyl 2-ylidene-acetate), which is suitable for a subsequent post-polymerization modification under mild reaction conditions via copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The post-modification reaction results in quantitative conversions, and provides an efficient and general route for the selective post-modification of C1 polymers with a variety of azide compounds. The structure of the poly(propargyl 2-ylidene-acetate) was confirmed and characterized by NMR, FT-IR, and GPC techniques. Upon comparison with results on post-polymerization modification of the corresponding C2 polymer, poly(propargyl acrylate), no obvious influence on the reactivity towards the post-modification of acetylene group on the C1 polymer precursor was observed. Noteworthy, the introduction of pentafluorophenyl azide facilitated a subsequent second modification via the Para-Fluoro-Thiol reaction (PFTR). Accordingly, cascade post-modifications of C1 polymers yielded novel polymethylenes that are not accessible by direct C1 polymerization.

Automated summary

Rhodium(I)-catalyzed C1 polymerization of propargyl 2-diazoacetate was successfully conducted for the first time, resulting in a novel poly(propargyl 2-ylidene-acetate) derivative suitable for subsequent post-polymerization modification. The post-modification reactions exhibit high reactivity and provide an efficient and general route for selective modification of C1 polymers. Furthermore, the introduction of pentafluorophenyl azide facilitates a subsequent second modification via the Para-Fluoro-Thiol reaction, leading to the synthesis of novel polymethylenes not accessible by direct C1 polymerization.