Efficient Piancatelli rearrangements of HMF derivatives under microwave activation or subcritical water conditions to produce functionalized hydroxylated cyclopentenones

HMF (5-hydroxymethylfurfural), a renewable raw material from biomass, was used as starting material to provide 5-aryl-4-hydroxymethyl-4-hydroxycyclopentenones with functionalized aryl groups. In a first time, arylic substituents were added to the aldehyde moiety of HMF under rhodium- or palladium-catalyzed 1,2-addition of arylboronic acids, in mild conditions to respect the very sensitive HMF reactivity. In a second time, these non-symmetrical furan-2,5-dicarbinols, through Piancantelli rearrangement, provided the desired cyclopentenones under microwave activation or subcritical water conditions (100 °C and 100 bars) using the Zippertex technology, in regio- and diastereoselective manner. These synthetized bis-hydroxylated cyclopentenone derivatives exhibited significant antimicrobial activities against gram-positive bacteria Micrococcus luteus, Bacillus subtilis and gram-negative bacteria Echerichia coli.