One-Pot Synthesis of Alkyl 4-alkyl-2,8-dioxo-2H,8H-pyrano[2,3- f]chromene-10-carboxylates and Alkyl 2(E)-3-[(4-alkyl-2-oxo-2H-chromen- 7-yl)oxy]acrylates

We report the synthesis of novel alkyl 4-alkyl-2,8-dioxo-2H,8H-pyrano[2,3-f]chromene-10-carboxylates by the reaction of 7-hydroxy coumarins and dialkyl acetylenedicarboxylates in the presence of triphenylphosphine, when alkyl propiolates were employed O-vinylated coumarin derivatives were obtained.