Mechanistic Investigations into the Catalytic Levulinic Acid Hydrogenation, Insight in H/D Exchange Pathways, and a Synthetic Route to d₈-γ-Valerolactone

γ-Valerolactone (GVL) is readily accessible by catalytic hydrogenation of carbohydrate-derived levulinic acid (LA) and an attractive biobased chemical with a wide range applications in both the (e.g., as biomass-derived solvent) transportation fuel sector. In this study, we used isotopic labeling experiments to provide insights into pathways involved conversion LA GVL under different reaction conditions using water environmentally benign solvent Ru/C available catalyst. 2H NMR combined quantum calculations revealed that deuterium atoms can be incorporated at positions well involvement intermediates 4-hydroxypentanoic α-angelica lactone (α-AL). The insight provided these studies yet unexploited sequential deuteration route synthesize fully deuterated GVL. starts α-AL followed selective acidic protons H/D exchange D2O. Subsequent ring-opening D2O (d2-AL d3-LA) remaining d3-LA via keto-enol tautomerization heating gives d8-LA. Finally, d8-LA catalytically reduced low temperature D2 d8-GVL.