What would you expect as a major product when 1-pentene undergoes hydroboration-oxidation?

When 1-pentene undergoes hydroboration-oxidation, the expected major product is 2-pentanol. This reaction involves two key steps: hydroboration and oxidation.

In the hydroboration step, diborane (B2H6) adds across the double bond of 1-pentene in a syn addition mechanism, leading to the formation of an organoborane intermediate. This is a crucial phase because boron adds to the less substituted carbon of the alkene due to steric and electronic factors, resulting in the formation of a trialkyl borane. In the case of 1-pentene, this means that boron attaches to the terminal carbon (C1), while the hydrogen attaches to the second carbon (C2).

During the oxidation step, the organoborane is then treated with hydrogen peroxide (H2O2) in a basic medium, which results in the replacement of the boron moiety with a hydroxyl group. This transformation leads to the generation of an alcohol where the hydroxyl group ends up on the more substituted carbon (C2 in this case), resulting in the formation of 2-pentanol.

This regioselectivity is a fundamental aspect of