Synthesis of 12-oxa, 12-aza and 12-thia cholanetriols

▶ An easy access to 12-hetero steroids is described. A photolysis and a Baeyer-Villiger oxidation are the key steps of these syntheses. ▶ Cholic acid, an inexpensive bile acid, is used as starting material. ▶ The first synthesis of an 12-aza steroid is described via 9 steps and a good overall yield.