Nazar Flaih, James R. Hanson, Peter B. Hitchcock and Ismail Kiran
The preparation of some substituted androstane 4- and 6-ketones is described revealing further examples of neighbouring group participation between substituents at C-4 and C-6; the X-ray crystal structure of androstane-4,6,17-trione showed that it existed in a form that was a hybrid of the Δ4- and Δ6-enolates.