Synthesis of some 3,4-dihydro-2H-benzo[f]pyrano[2,3-h]chromen-6-one derivatives

Abstract

Reactions of o-quinones 16–18 with ylide 19 afforded compounds 5–7 in moderate to good yields (62–80%), which were further de-ethoxycarbonylated to compounds 28–30 in 53–66% yield. Compounds 6, 7 and 29 were further transformed into compounds 31–35. The preparation of the novel compounds 10, 11, 16 and 27 is also reported.