σ-bishomoaromatic heterocycles: Reactivity and synthesis of 3-oxatetracyclo[3.3.0.02,804,6]octane by photolysis at 185 nm

Article abstract of DOI:10.1016/0040-4039(96)00062-7

The title compound 5 was produced by 185 nm photolysis of 8. The products of the 185 run photolysis can be rationalized by the assumption of the two diradical intermediates 16 and 17. At a temperature between 150 and 200°C 5 reacts with fumaronitrile 23 to give the adducts 7 and 26 in a ratio of about (5 : 1). The kinetic analysis of this reaction shows, that the adduct 7 is formed by 1,3 dipolar cycloaddition of intermediate carbonyl ylide 6.