Mechanical Insight into the Green Oxidation of Bio-Based LGO to Produce HBO: The Effect of Hydrogen Peroxide Solution.

Converting biomass-derived levoglucosenone (LGO) into (S)-γ-hydroxymethyl-α,β-butenolide (HBO) via a catalyst-free process using H2O2 solution offers a green route to valuable chiral intermediates. However, the molecular pathway controlling selectivity and energy efficiency remains unknown. This work adopts quantum chemistry calculations coupled with electronic structure and kinetic analyses to elucidate the formation mechanism of HBO from LGO, with a focus on the role of H2O2 solution. HBO chiefly forms via Baeyer-Villiger oxidation (BVO) of LGO, followed by hydrolysis, with (5-oxo-2,5-dihydrofuran-2-yl)methyl formate (FBO) as a key intermediate. H2O2 solution acts as both an oxidant and a catalytic medium, where surplus H2O2 and H2O molecules form hydrogen-bonded clusters to shuttle protons and stabilize transition states. The H2O2 cluster is more effective than the H2O2-H2O cluster in reducing the ring tension of transition states (148.8 kJ/mol vs 157.0 kJ/mol).