The intramolecular dioxenone photocycloaddition reaction provides access to compounds which in many cases cannot be otherwise prepared. The application of this methodology to the construction of trans-bicyclo[4.4.1]undecan-11-one, 16, which is ca. 10 kcal/mol more strained than the corresponding cis-bridged isomer, is described. The extension of this preliminary result to the first synthesis of the tricyclic ingenane nucleus with the requisite "inside-outside" or trans intrabridgehead stereochemical relationship is reported.