Additionsreaktionen der nitrosogruppe—XV : [2+4]- Und [2+6]-cycloaddukte von nitrosobenzolen mit cyclischen dienen und trienen

1,3-cyclooctadiene, 1,3,6-cyclooctatriene and bicyclo-4.2.0]-2,4-octadiene give normal Diels-Alder-adducts with nitrosobenzenes. In the reaction of 1,3,5-cyclooctatriene with nitro-substituted nitrosobenzenes, too, 2+4]-cycloadducts are formed which, however, rearrange by heating in solution to 2+6]-cycloadducts. These isomers are the only products isolated in the addition of nitrosobenzene and its p-chloro derivative to the triene.