Hydrogenation of Cyclic 1,3-Diones to Their 1,3-Diols Using Heterogeneous Catalysts: Toward a Facile, Robust, Scalable, and Potentially Bio-Based Route

Cyclopentane-1,3-diol (4b) has gained renewed attention as a potential building block for polymers and fuels because its synthesis from hemicellulose-derived 4-hydroxycyclopent-2-enone (3) was recently disclosed. However, cyclopentane-1,3-dione (4), which is constitutional isomer of 3, possesses higher chemical stability can therefore afford carbon mass balances yields 4b in the hydrogenation reaction under more concentrated conditions. In this work, 4 into over commercial Ru/C catalyst systematically investigated on bench scale through kinetic studies variation Herein, temperature, H2-pressure, solvent choice were found to have significant effects rate suppression undesired dehydration 4. The cis–trans ratio naturally generated 7:3 these reactions. at elevated temperatures, epimerizes, yielding trans products. This effect also studied rationalized thermodynamic perspective using DFT. combined optimized conditions provided 78% yield 4b, successful applications 8-fold scaled up reactions (40 g) substrate scope several 1,3-diones demonstrate general applicability catalytic approach.