Direct synthesis of 5-methylfurfural from D-fructose by iodide-mediated transfer hydrogenation.

Herein, we firstly report a robust catalytic system 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 6 consecutive cycles without any decrease in the yield. Various starch and raw biomass could be served 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.