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A simple, catalyst free, water mediated, one pot four component, green protocol was developed for title compounds 7 starting from aromatic aldehydes (1), malononitrile (2), 1,3-diones (3) and N-chlorosuccinimide (NCS) in a sequential addition reaction at ambient temperature. The approach presented herein, for the first time, is through an unusual rearrangement where NCS was reacted with 2-amino-7,7-dimethyl-5-oxo-4-aryl-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (4), which was formed by the Knoevenagel condensation of aldehyde and malononitrile followed by the Michael addition of 3. In addition, this novel protocol is compatible with various aldehydes and active C-H functional derivatives, accomplishes high yields and follows the GAP chemistry principle. Interestingly, compound 4 when reacted with NCS in alcohol medium gave 2-cyano-6,6-dimethyl-4-oxo-3-aryl-2,3,4,5,6,7-hexahydrobenzofuran-2-carboxylate (5).

Synthesis of a series of novel aryl and heteroaryl fused 2,8-dioxabicyclo[3.3.1]nonanes (3) was accomplished by one pot, catalyst free reaction of 2-hydroxy chalcones (1) with 3-trifluoromethyl substituted pyrazolones (2) in xylene at reflux temperature. The role of –CF3 in formation of 3 was confirmed by comparing with 3-methyl pyrazolones.