The title compound 5 was produced by 185nmphotolysis of 8. The products of the 185nmphotolysis can be rationalized by the assumption of the two diradical intermediates 16 and 17. At a temperature between 150 and 20 °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