The cheletropic trapping of nitric oxide by the bis-ketene 1,2-dicarbonylcyclohexa-3,5-diene and the diene 3,4-diphenyl-2,5-dimethyl-2,4-hexadiene.

We report the first example of the cheletropic trapping of nitric oxide with a bis-ketene. In the presence of nitric oxide the bis-ketene 12-dicarbonylcyclohexa-3,5-diene (1), generated from photolysis of benzocyclobutenedione, gave N-hydroxyphthalimide (5) and phthalic anhydride (7); additionally, cheletropic NO trapping with 3,4-diphenyl-2,5-dimethyl-2,4-hexadiene (3) gave strong persistent ESR signals, the nature of which was dependent on the purity of the NO.