Hydroarylation of carbon–carbon double bond of furanic conjugated enones by arenes under superelectrophilic activation: synthesis and evaluation of antimicrobial activity of novel furan derivatives

Various furanic conjugated enones, 4-(furan-2-yl)but-3-en-2-ones and 1-aryl-3-(furan-2-yl)prop-2-en-1-ones, have been synthesized from furfural, 5-hydroxymethylfurfural, and its derivatives by aldol condensation. It has been found for the first time, that reactions of these furanic conjugated enones with arenes under the action of triflic acid or AlCl3 afford the corresponding products of hydroarylation of the furan side chain carbon–carbon double bond in 29–89% yields. According to NMR study and DFT calculations, the corresponding O,C-diprotonated species of furanic enones are the reactive electrophilic intermediates. The obtained furan derivatives demonstrate moderate antimicrobial activity against yeast-like fungi Candida albicans at 64 μg/ml concentration. They also suppress Escherichia coli and Staphylococcus aureus.