Stereoselective Transition-Metal-Free Diboration of Alkenes

Abstract

Boronates are extremely useful in synthesis due to the ability of carbon-boron bonds to be transformed into carbon-oxygen, carbon-nitrogen, or carbon-carbon bonds stereospecifically. This makes the stereoselective construction of carbon-boron bonds especially useful. The development of transition-metal catalyzed diboration of alkenes gave synthetic organic chemists a way to quickly make not one, but two carbon-boron bonds in a stereoselective fashion. However, there are many drawbacks to transition-metal catalysis, such as high cost of catalysts and chiral ligands, and air and moisture sensitivity of catalysts. These issues, in addition to difficulties in removing trace amounts of metal contaminants from reaction products have prevented transition-metal-catalysis from being used on the industrial scale. Discussed in this thesis are two different methods for stereoselective, transition-metal-free diboration of alkenes developed by the Morken group. Also discussed is the pioneering work in the area of transition-metal-free diboration done by the Fernández group, which inspired these methodologies.