Versatile CO-assisted direct reductive amination of 5-hydroxymethylfurfural catalyzed by a supported gold catalyst

Reductive amination (RA) constitutes an attractive and practical strategy for discovering protocols capable of converting biomass into valuable N-containing compounds. Described herein is a versatile and sustainable RA of 5-hydroxymethyl-furfural (HMF), an important biomass-derived aldehyde, using abundant and cheaply available CO and water as reductants. A single phase rutile titania supported gold (Au/TiO2-R) catalyst is shown to efficiently catalyze this CO/H2O-mediated RA under mild and convenient conditions. With this system, a broad spectrum of primary and secondary amines can be used as suitable substrates and the desired reaction can proceed favourably in a highly chemoselective, efficient and atom-economical fashion. In particular, this protocol can also allow convenient access to bis(hydroxylmethylfurfuryl)-amines, a new group of furan-based monomers with great potential to form functional biopolymers with tunable properties. Moreover, this CO-assisted RA is more efficient (higher TON and TOF) and more eco-friendly (increased resource efficiency) than the previous state-of-the-art technique.