Illustrated Glossary of Organic Chemistry

Hydroboration: The addition of the B-H bond of a borane across a carbon-carbon pi bond of an alkene or alkyne to form an organoborane. The organoborane is usually not isolated from the reaction mixture, but instead reacted in situ in various ways to form a wide range of functional groups. Herbert C. Brown (Purdue University) shared the 1979 Nobel Prize in Chemistry for developing and exploring this versatile process.

In this hydroboration example, 1-methylcyclohexene is hydroborated with borane (BH3). The resultant organoborane intermediate can be converted to a variety of functional groups, depending upon what it is reacted with. For example reaction of the organoborane with HOOH and NaOH gives an alcohol (the hydroboration-oxidation reaction). Or, reaction of the organoborane with NaOH and I2 forms an iodoalkane (hydroboration-iodination).