Tetraethylammonium Fluoride-mediated A Green Hydrogen Transfer Process for Selective Reduction of Biomass-derived Aldehydes

Hydrogenation of furfural (FUR) to furfuryl alcohol (FFA) is a key step and one of the representative examples for comprehensive utilization of biomass, while relatively harsh conditions are typically required to achieve satisfactory results using molecular hydrogen, formic acid, or alcohol as H-donor over expensive metal catalysts. In this work, a new and benign reaction system, composed of green and cheap tetraethylammonium fluoride and polymethylhydrosiloxane (PMHS), is developed to be efficient for transfer hydrogenation of bio-based FUR to high-value FFA under mild conditions. After reacting at 35 ℃ for 0.5 h, 94.9% FUR conversion and 92.3% yield of FFA could be achieved. This protocol is also widely applicable to the selective reduction of various aromatic aldehydes, giving relevant alcohols in high yields of 81.0-99.9% at 35-60 °C within 30-120 min. Moreover, the mechanism of fluoride-activated hydrosilylation was demonstrated to be responsible for the efficient transfer hydrogenation process.