A Facile One-Pot Synthesis of Functionalized 4,8-Dihydropyrano[3,2-b]-pyran-4-ones

The reactive intermediates generated by the addition of alkyl isocyanides and dialkyl acetylenedicarboxylates were trapped by 5-hydroxy-2-hydroxymethyl-4H-pyran-4-one (kojic acid) to yield functionalized 4,8-dihydropyrano[3,2-b]- pyran-4-ones at ambient temperature in good yields.