Photochemical ring-contraction of fused bicyclic 4-pyrones: A novel 2-step cyclopentannulation approach

Article abstract of DOI:10.1016/S0040-4039(00)60630-5

Fused bicyclic 4-pyrones were prepared by condensation of enamines derived from cyclic ketones with diketene or substituted 1,3-dioxin-4-ones. Photolysis in a hydroxylic medium led to bicyclo [n3.0]alkenones bearing oxygenation at both angular positions.