Chapter 12, Problem 12.43P

Interpretation Introduction

(a)

Interpretation:

How to prepare the given compound from an alkene is to be explained.

Concept introduction:

The acid-catalyzed hydration of an alkene is the electrophilic addition of water across the $\text{C=C}$ bond in an acidic condition. The electrophilic addition reaction of an alkene occurs through formation of a more stable carbocation. The reaction proceeds with proton transfer reaction to form a stable carbocation, followed by the action of water as a nucleophile, forming the corresponding alcohol. The order of stability of carbocation is ${\text{CH}}_{\text{3}}\text{}{\text{< 1}}^{\text{o}}{\text{ < 2}}^{\text{o}}{\text{ < 3}}^{\text{o}}$. The carbocation can be rearranged by $\text{1, 2-}$ hydride or $\text{1, 2-}$ methyl shift to form a more stable carbocation.

The oxymercuration-reduction is also the reaction of addition of water through the $\text{C=C}$ bond. The alkene is first reacted with mercury $\left(\text{II}\right)$ acetate, $\text{Hg}{\left(\text{OAc}\right)}_{\text{2}}$, in water–tetrahydrofuran (THF) solution, and that is followed by reduction with sodium borohydride, ${\text{NaBH}}_{\text{4}}$. The mechanism follows the Markovnikov rule and adds $\text{OH}$ to more substituted double bonded carbon. The reaction proceeds through formation of a Mercurinium ion intermediate, and there is no formation of a carbocation. Thus, the rearrangement is not possible in oxymercuration-reduction.

Interpretation Introduction

(b)

Interpretation:

How to prepare the given compound from an alkene is to be explained.

Concept introduction:

The acid-catalyzed hydration of an alkene is the electrophilic addition of water across the $\text{C=C}$ bond in an acidic condition. The electrophilic addition reaction of an alkene occurs through formation of a more stable carbocation. The reaction proceeds with proton transfer reaction to form a stable carbocation, followed by the action of water as a nucleophile, forming the corresponding alcohol. The order of stability of carbocation is ${\text{CH}}_{\text{3}}\text{}{\text{< 1}}^{\text{o}}{\text{ < 2}}^{\text{o}}{\text{ < 3}}^{\text{o}}$. The carbocation can be rearranged by $\text{1, 2-}$ hydride or $\text{1, 2-}$ methyl shift to form a more stable carbocation.

The oxymercuration-reduction is also the reaction of addition of water through the $\text{C=C}$ bond. The alkene is first reacted with mercury $\left(\text{II}\right)$ acetate, $\text{Hg}{\left(\text{OAc}\right)}_{\text{2}}$, in water–tetrahydrofuran (THF) solution, and that is followed by reduction with sodium borohydride, ${\text{NaBH}}_{\text{4}}$. The mechanism follows the Markovnikov rule and adds $\text{OH}$ to more substituted double bonded carbon. The reaction proceeds through formation of a Mercurinium ion intermediate, and there is no formation of a carbocation. Thus, the rearrangement is not possible in oxymercuration-reduction.