Novel Photochemical Reactions of 3(2H)-Furanones

Article abstract of DOI:10.1021/jo00224a009

Irradiation (λ <*> 280 nm) of furanones 6-9 leads to rearrangement to enol lactones 14-17, while the di-tert-butyl-substituted derivative 10 undergoes decarbonylation to form 21.Both types of reaction are readily quenched by 2,3-dimethyl-1,3-butadiene, and a common mechanism is suggested, involving rearrangement of the furanone to an acylcyclopropanone (as 18), followed by either reverse <1,3> shift to furnish enol lactone or alternatively decarbonylation to yield 21.A convenient route to 3(2H)-furanones is provided by mercuric acetate oxidation of readily available allenic ketones.