[6]paracyclophane (1) has been synthesized by oxidative decarboxylation of [6.2.2]propellenecarboxylic acid with leadtetraacetate. Vapor phase thermolysis of 1 affords 3-methylene-spiro[5.5]undeca-1,4-diene predominantly, while acid-catalyzed rearrangement of 1 gives the meta and ortho isomers in a ratio of 1:3.