Question

Which reagent converts  \(propene\) to \(1-propanol\):

• A. \(H_2O, H_2SO_4\)
• B. \(B_2H_6, H_2O_2, OH^–\)
• C. \(Hg(OAc)_2, NaBH_4/H_2O\)
• D. \(Aq. KOH\)

Answer 1

The Correct Option is B

To convert propene to 1-propanol, we need to perform an anti-Markovnikov hydration of the alkene. This reaction is typically achieved through hydroboration-oxidation.

1. Hydroboration: In the first step, B_2H_6 (diborane) is used. Diborane adds across the double bond of propene, where the boron atom attaches to the less substituted carbon (the terminal carbon), consistent with anti-Markovnikov rule.
2. Oxidation: The organoborane intermediate formed in the hydroboration step is then oxidized using hydrogen peroxide (H_2O_2) in a basic medium (OH^-). This converts the boron atom to a hydroxyl group, thus forming 1-propanol.

Thus, the reagent B_2H_6, H_2O_2, OH^– effectively converts propene to 1-propanol by this mechanism. Let us analyze other options:

• H_2O, H_2SO_4: This typically leads to Markovnikov hydration, forming 2-propanol.
• Hg(OAc)_2, NaBH_4/H_2O: Known as oxymercuration-demercuration, this also leads to Markovnikov addition, which forms 2-propanol.
• Aq. KOH: This is not suitable for converting alkenes to alcohols; rather, it is commonly used for substitution and elimination reactions.

Therefore, the correct choice is using B_2H_6, H_2O_2, OH^– for converting propene into 1-propanol.