MOF-catalyzed hydroxyalkylation-alkylation reaction for the controlled synthesis of furan oligomers

Hydroxyalkylation-alkylation (HAA) reaction is a type of C-C coupling technique utilized in the production of furan oligomers, which are potential biofuel precursors. In this study, we present the first application of an acidic MOF, Sulfated MOF-808, in catalyzing the HAA reactions of a series of furan oligomers with high yield and selectivity. Specifically, we focused on the optimization of the HAA between 5-methylfurfural (5-MFUR) and 2methylfuran (2-MF) by varying different reaction conditions, which afforded a quantitative yield reaching 97% while preventing the self-condensation of 2-MF. The catalyst was also found to be recyclable and can be reused without significant loss in its activity. Lastly, we extended the substrate scope to include benzene-based electrophiles, thereby further proving the versatility of the Sulfated MOF-808 catalyst in the HAA reactions of a variety of starting materials.