Rapid preparation of 3-deoxyanthocyanidins and novel dicationic derivatives: New insight into an old procedure

Common 3-deoxyanthocyanidins and original dicationic flavylium-benzopyrylium derivatives are easily and efficiently synthesized through reactions between the corresponding phenols and aryl ethynyl ketones in the presence of aqueous hexafluorophosphoric acid. The mechanism of the reaction is discussed and two competitive pathways are consistent with our results. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim., Germany, 2007).