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

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 gcat -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.