Valorisation of Biomass-Derived Platform Molecules

Abstract

Conventional chemistry in the 20th and 21st centuries is hinged on the extraction and manipulation of non-renewable, fossil-derived chemical feedstocks. This thesis details new efforts to pivot towards the valorisation of sustainable biomass-derived platform molecules as a source of commodity chemicals. Primarily, the work involves the utilisation of levoglucosenone, a compound available in the kiloton scale from the pyrolysis of acid-treated cellulosic waste. In Chapter 2, the landscape of sustainable platform molecules is described, as well as the existing work performed on levoglucosenone, giving context to the experimental work reported herein. Chapter 3 is an experimentally based article which provides a novel synthesis of iso-levoglucosenone, the quasi-enantiomer of levoglucosenone, formed through a new and synthetically concise 1,3-carbonyl transposition. This approach was also compared to an alternate synthesis from D-glucose. This material was then hydrogenated to form a novel potential solvent (iso-Cyrene), the properties of which were compared to the levoglucosenone-derived solvent Cyrene. Chapter 4 provides novel transformations of levoglucosenone and iso-levoglucosenone-derived Diels-Alder adducts using several dienes, including the biomass-derived a-terpinene. The products of these cycloadditions were then subjected to reduction of the carbonyl to afford diastereomeric alcohols, which could then be transformed using Wagner-Meerwein rearrangements and intramolecular bromoetherifications. These fully characterised products give novel and distinct chemical structures. Finally, Chapter 5 describes the most direct polymerisation of levoglucosenone reported to date, facilitated using a catalytic amount of nucleophilic base. This polymer was obtained in quantitative yields and with relatively high molecular weights. Further, the material was functionalised using a green Baeyer-Villiger oxidation to give an extremely hydrophilic and freely water-soluble polymer.