Direct Synthesis of 5-Methylfurfural from d-Fructose by Iodide-Mediated Transfer Hydrogenation

Graphical Transfer hydrogenation : 5-Methylfurfural (5-MF), a promising C 6 platform molecule, is directly produced from biomass-derived carbohydrates by iodide-mediated transfer hydrogenation. Under the optimized conditions, 30–50 % of 5-MF is yielded from low-cost sugars and starch with 5-MF productivity as high as 103 mmol g cat −1 h −1 . The catalytic system is simple, robust, recyclable, and preferable to other approaches for the production of 5-MF. Herein, a robust catalytic system was developed for the green synthesis of 5-methylfurfural (5-MF) by iodide-mediated transfer hydrogenation. Around 50 % of 5-MF was yielded from d -fructose within 7.5 min using NaI as the catalyst and formic acid as both the hydrogen source and co-catalyst. The catalytic system was used for six consecutive cycles without any decrease in the yield. Various starch and raw biomass could be used as promising starting materials for 5-MF synthesis with moderate yields, and the productivity of 5-MF from corn starch reached 103 mmol g cat −1 h −1 , which is comparable with the best result from l -rhamnose. Moreover, the co-production of 5-MF and furfural from raw biomass makes this methodology more competitive than other routes.