Oxygen-Doped Cobalt Disulfide Accelerates the Controlled Hydrogenative Rearrangement of Furfurals to Cyclopentenones

Selective hydrogenative rearrangement of bio-derived furfurals (e.g., 5-methylfurfural, furfural, and 5-hydroxymethylfurfural) to cyclopentenones (e.g., 3-methylcyclopentenone and cyclopentenone) is promising for the production of high-value chemicals. In this work, surface-oxidized cobalt disulfide (CoS2–O) was synthesized, and it exhibited a highly selective hydrogenative rearrangement of 5-methylfurfural to 3-methylcyclopentenone in an unprecedented yield of 61.8%. Catalytic mechanism studies revealed that the surface oxidation of CoS2 promotes the generation of Co3+ sites, providing the hydrogenation sites for the conversion of 5-methylfurfural to 5-methylfurfuryl alcohol and offering the Lewis acid sites for the ring opening of 5-methylfurfuryl alcohol. Furthermore, the catalyst exhibited broad catalytic applicability to other furfurals. This study presents a challenging tandem pathway for the green synthesis of cyclopentenones.