PHOTOCHEMISTRY OF 5-ARYL-2(3H)-FURANONES. A NEW ROUTE TO THE SYNTHESIS OF CHROMONES

Article abstract of DOI:10.1016/S0040-4020(01)97966-9

The photochemistry of 5-phenyl-, 5-(2',5'-dimethoxyphenyl)-, 5-(2'-acetoxy-5'-methoxyphenyl)- and 5-(2',5'-diacetoxyphenyl)-2(3H)-furanone (1a-d) has been investigated.Compound 1a yields pheny vinyl ketone as expected.Similarly, 1b affords the corresponding aryl vinyl ketone but, in this case, photodimerization also occurs.Irradiation of the two o-acetoxyaryl furanones 1c and 1d gives rise to the formation of chromones as the main products.This interesting result can be accounted for in terms of a photochemical opening of the lactonic ring followed by radical addition to the acetoxy group.