The chemistry of the tropilidene (2+4)-and (2+6)-and the norcaradiene (2+4)-cycloadducts, respectively 2a, 2c, and 2b, of 1, 3, 5-cycloheptatriene with singlet oxygen was studied, including their thermolysis, photolysis, rearrangement in methanol, and triphenylphosphine deoxygenation. The respective oxygen diradicals are postulated as precursors to the thermal and photochemical products. In the course of this investigation, the stereospecific syntheses of the bisepoxides 4a and 3c of tropilidene and the bisepoxide 3b of norcaradiene were accomplished. © 1979, American Chemical Society. All rights reserved.