Question

What is meant by hydroboration-oxidation reaction? Illustrate it with an example.

Illustrate the hydroboration-oxidation reaction with an example.

Answer 1

The addition of borane followed by oxidation is known as the hydroboration-oxidation reaction. For example, propan-1-ol is produced by the hydroboration-oxidation reaction of propene. In this reaction, propene reacts with diborane (BH₃)₂ to form trialkyl borane as an addition product. This addition product is oxidized to alcohol by hydrogen peroxide in the presence of aqueous sodium hydroxide.

\[\ce{\underset{Propene}{CH3 - CH = CH2} + BH3 -> CH3 - CH2 - CH2 - BH2 ->[CH3CH = CH2](CH3 - CH2 - CH2)2BH ->[CH3CH = CH2] \underset{Addition reaction}{(CH3 - CH2 - CH2)3B} ->[H2O/H2O/\overset{-}{O}H]\underset{Propanol}{3CH3 - CH2 - CH2 - OH}}\]