Poly(5-hydroxyoctenylene) and Its Derivatives: Synthesis via Metathesis Polymerization of an Organoborane Monomer

The synthesis of a new monomer, (5-cyclooctenyl)diethylborane, and its polymerization by ring-opening metathesis are reported. This resultant polyborane rendered a novel polymer, poly(5- hydroxyoctenylene), upon oxidation. The hydroboration/oxidation reactions can be controlled to give polymers with varying amounts of hydroxyl groups on the backbone. The structure of the polyalcohols was confirmed by^lH NMR and¹³C NMR spectroscopy. In addition,¹³C NMR spectroscopy confirmed the presence of various 1,4-, 1,5-, and 1,6-diol sequences in the completely hydroxylated polymer. The glass transition temperatures of the polymers were fairly low and lie between 10 and 45 °C. The polymers are thermally stable and begin to lose weight only at temperatures above 400 °C, compared to polyvinyl alcohol), which undergoes weight loss at temperatures as low as 300 °C.