Question

Choose the correct option for the following reactions. 
 

• A. A and B are both Markovnikov addition products.
• B. A is Markovnikov product and B is anti-Markovnikov product.
• C. A and B are both anti-Markovnikov products.
• D. B is Markovnikov and A is anti-Markovnikov product.

Hint:

Hydroboration-oxidation is a two-step reaction where the hydroboration step follows the anti-Markovnikov rule, while the oxidation step gives the Markovnikov alcohol.

Answer 1

The Correct Option is B

In the given reaction, the addition of \( BH_3 \) to the alkene is carried out under hydroboration conditions. The hydroboration step follows the anti-Markovnikov rule, meaning that the boron atom adds to the carbon with fewer hydrogen atoms, leading to the formation of the intermediate organoborane. 
In the next step, the reaction proceeds with oxidation and hydrolysis, which converts the organoborane to an alcohol. The final product \( A \) is formed following the Markovnikov rule, as the hydroxyl group (-OH) will add to the more substituted carbon. Therefore, \( A \) is the Markovnikov product, and \( B \) is the anti-Markovnikov product.