Selenium Stabilized Carbenium Ions on Organic Synthesis

Organoselenium compounds have been known for a long time as versatile reagents in organic chemistry. In the last years there has been a considerable development of selenium-based methods for organic synthesis. Many of these methods are currrently been used as standard procedures to introduce new functional groups under mild conditions. From the several areas of interest in organoselenium chemistry, selenium stabilized carbocations has emerged as a useful class for interesting transformations and new methods for carbon-carbon bond formation. Aspects related to heterosubstituted carbenium ions, like their formation, structure and stability, has been very well studied and revised by Hevesi in the last years, and will not be the subject of this article. In the following chapter we will detail synthetic aspects of selenium stabilized carbocations as electrophiles.