Q44Ec - Organic Chemistry (Mcmurry)

Question

Question: Predict the products of the following reactions, showing both regiochemistry and stereochemistry where appropriate:

Step-by-Step Solution

Answer

Answer

Product of the reaction (c) is:

Step 1: Hydroboration oxidation reaction

Hydroboration-oxidation reaction means transformation of alkenes into alcohols. Across an alkene, the net addition of water takes place during this type of reaction.

Step 2: 1 . B H 3 ,   T H F ,   2 .   H 2 O 2 ,   H O - Reagent

The reaction that takes place in the presence of reagent ($1.B{H}_3, THF, 2. H_2{O}_2$) is known as hydroboration- oxidation reaction. H.C Brown discovered this reaction in 1959. In this reaction borane $\left(B{H}_3\right)$ act as an electrophile due to the presence of empty p orbitals and as this is an explosive gas, therefore, we always use this in the presence of solvent THF (Tetrahydrofuran).

This complex will act as an electrophile and it will do hydroboration reaction and afterwards in the presence of $H_2{O}_{2, }H{O}^{-}$ oxidation reaction will take place. 

Step 3: Product of reaction

In the reaction, reactant is alkene and it is a nucleophile and the complex $B{H}_{3 }-THF$is an electrophile. The addition of complex on an alkene is a concerted reaction i.e. bond making and bond breaking takes place simultaneously. After that in the presence of $H_2{O}_{2, }H{O}^{-}$, hydroxide ion will replace boron atoms and that will attach according to anti-Markovnikov’s rule. The product of the reaction will be: