Multicomponent synthesis of a novel bicyclic pyran-2-one system

A one-pot procedure was developed for synthesis of a new series of pyran-2-one products, based on the combination of cyclohexanone with malononitrile and aromatic aldehydes. Reactions take place in an aqueous alcoholic medium at elevated temperature in relatively short time periods, directly giving the products by spontaneous precipitation in the vessel. The final formation of the aromatic pyran-2-one system occurs in situ under molecular iodine catalysis. Monitoring of the reactions suggested the intervention of the respective bisarylidene and amino-4 H -chromene intermediates in the process. These intermediates were synthesized separately and converted to the same final products to support that the reaction proceeds through the suggested mechanism. Graphical abstract