Synthesis of Functionally and Stereochemically Diverse Polymers via Ring-Opening Metathesis Polymerization of Derivatives of the Biomass-Derived Platform Molecule Levoglucosenone Produced at Industrial Scale
Martin G. Banwell, Xin Liu, Luke A. Connal, Michael G. Gardiner
Abstract
The commercially available, abundant and homochiral cellulose pyrolysis product levoglucosenone (LGO) together with the readily derived isolevoglucosenone (isoLGO) form, in a stereoselective manner, Diels–Alder adducts with cyclopentadiene (CPD). These ring-fused norbornene systems, each of which incorporates six centers of chirality and is pseudoenantiomeric in nature, undergo ring-opening metathesis polymerization (ROMP) in the presence of a range of ruthenium-based catalysts to produce polymers embodying both carbo- and heterocyclic motifs. Under such conditions, controlled polymerizations take place with target molecular weights matching the theoretical ones and with low dispersities (from 1.1 to 1.4) normally being observed. Reduction of the carbonyl group in the Diels–Alder adduct derived from LGO provides the corresponding epimeric alcohols that can be etherified and the resulting ethers, including fluorine-containing ones, also yield well-controlled polymers via ROMP. This thus represents an efficient method for producing stereochemically and functionally diverse polymers from a renewable feedstock available at an industrial scale. These polymerizations are living ones as demonstrated by the facile preparation of block copolymers from the two Diels–Alder adducts.