Green synthesis of 2-deoxy-D-ribonolactone from cellulose-derived levoglucosenone (LGO): A promising monomer for novel bio-based polyesters

Abstract

The already reported, yet hazardous, Et3N-catalyzed levoglucosenone (LGO) hydration into 1,6-anhydro-3-deoxy-β-D-erythro-hexo-pyranose-2-ulose (LGO-OH) has been greened up by substituting Et3N with K3PO4 and performing the reaction in H2O. Optimal reaction conditions (K3PO4 (0.05 eq.), [LGO] = 0.08 M, 5 h) not only allowed higher yields, but also limited the homocoupling of LGO, a competitive side reaction. A comparative – yet non-comprehensive and perfectible – Life Cycle Assessment (LCA) using the CML 2002 method highlighted the specific impacts where this revisited synthesis outperformed the Et3N-catalyzed one. 1,6-Anhydro-3-deoxy-β-D-erythro-hexo-pyranose-2-ulose was then subjected to a one-pot catalyst- and organic solvent-free Baeyer-Villiger oxidation/rearrangement, without the need to perform acidic hydrolysis, to access 2-deoxy-D-ribonolactone (HO-HBO, 79% yield). To assess the potential of HO-HBO as monomer for the production of novel bio-based polyesters, the latter was finally polymerized in the presence of aliphatic diacyl chlorides to make a proof-of-concept. Resulting polyesters exhibited promising glass transition temperature (Tg) values between −21 and −2 °C and melting temperatures (Tm) from 87 to 144 °C, demonstrating the potential of HO-HBO for the production of sustainable alternatives to current fossil fuel-based polymers.