A Library of Versatile Lignocellulose-Derived Monomers From 5-(Chloromethyl)furfural

The valorization of biomass-derived platform chemicals into functional monomers is a promising strategy for developing more sustainable polymeric materials. Herein, we report a versatile synthetic approach for the preparation of a library of lignocellulosic (LC) monomers by coupling 5-(chloromethyl)furfural (CMF), once considered a waste product of furan production, with selected lignin-derived monomers. The reaction was optimized using vanillin, affording a bis aldehyde monomer (Fur-Van) in 93% yield after only 2 h under mild conditions using K₂CO₃ as the base. The methodology was successfully extended to a range of lignin-derived substrates bearing different functional groups, providing a library of LC monomers in up to 94% isolated yield. The reactions were also successfully scaled up to 5 g of CMF. Products were isolated without any chromatographic purification. Furthermore, the reduction of the carbonyl groups afforded the corresponding (di)ol monomers in 87%-98% yield. Thermal characterization revealed good thermal stability of the synthesized compounds, with degradation temperatures above 220 °C for all the LC monomers. Overall, this work provides a straightforward and scalable route to multifunctional bio-based monomers combining lignin-derived aromatic structures with furanic moieties, offering promising building blocks for the development of bio-based polymeric materials.