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A simple and efficient method for the synthesis of highly functionalized furo[3,2- c ]coumarins was developed. The reaction occurred via initial formation of biscoumarins from the reaction of 4-hydroxycoumarins and aldehydes/aryl methyl ketones in the presence of molecular iodine in DMSO followed by lactone ring opening, cyclization and oxidative aromatization process. The reaction conditions were moderate, work-up procedure was simple and products were obtained in high yield. [ABSTRACT FROM AUTHOR]

Some dihydrofuro-fused coumarin derivatives were synthesized from 3-aminoalkyl-4-hydroxycoumarin via in situ generation ofN-ylide. The 3-aminoalkylated 4-hydroxycoumarin derivatives were synthesized from one-pot, three-component reaction of 4-hydroxycoumarin, aryl aldehydes, and secondary amines in ethanol at room temperature. Again, when salicylaldehyde was employed instead of benzaldehyde, interestingly pyranocoumarins were obtained. The reaction protocol can be further explored toward the synthesis of many other heterocyclic fused dihydrofurans. [ABSTRACT FROM AUTHOR]