Selenium as a Versatile Reagent in Organic Synthesis: More than Allylic Oxidation.

For many years since its discovery, Selenium has played the role of a bad boy who became a hero in organic transformations. Selenium dioxide, for instance, is one of the most remembered reagents in allylic oxidations, having been applied in the synthesis of several naturally occurring products. The main goal of this review is to show the recent advances in the use of classical and new selenium reagents in organic synthesis. As demonstrated through the around 60 references discussed here, selenium can go even forward as a versatile reagent. We bring a collection of selenium reagents and their transformations that still asleep in the eyes of most synthetic organic chemists.