Chapter 25, Problem 22P

Interpretation Introduction

Interpretation:

The major products that are formed from the given organic reaction are to be determined. The stereochemistry that exhibits by the diastereomeric products, if they are formed by these reactions is to be explained.

Concept Introduction:

The catalytic hydrogenation reaction is an addition reaction of hydrogen gas in a molecule in the presence of a catalyst. Aldehydic and ketonic molecules are reduced from this method and result in the formation of alcohol. Apart from hydrogen gas(presence of a catalyst) the other reducing agents are Lithium aluminum hydride, sodium borohydride and so on.

Answer to Problem 22P

Solution:

a) The principal organic product is.:

b) The principal organic product is:

c) The principal organic product is:

d) The principal organic product is:

e) The principal organic product is:

f) The principal organic product is:

g) The principal organic product is:

h) The principal organic product is:

i) The principal organic product is:

j) The principal organic product is:

Explanation of Solution

a) The given organic reaction isshown below.

${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{C}\equiv \text{C}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{COOH}+{\text{H}}_{\text{2}}\stackrel{\text{Lindlar Pd}}{\to }$

The given reaction is the hydrogenation of alkynes in the presence of Lindlar catalyst that reduces alkynes to alkenes. In the hydrogenation reaction of alkynes with Lindlar $\text{Pd}$, the addition of hydrogen atom is taken place on the same side of the alkynes results in the formation of cis alkenes and such addition called syn addition. The principal organic product of the given reaction is shown below.

b) The given organic reaction is shown below.

${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{C}\equiv \text{C}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{COOH}\underset{\text{2}{\text{. H}}^{+}}{\overset{\text{1}{\text{. Li, NH}}_{\text{3}}}{\to }}$

The given reaction is the hydrogenation of alkynes in the presence of ${\text{Li, NH}}_{\text{3}}$ that reduces alkynes to trans-alkenes. The principal organic product of the given reaction is shown below.

c) The given organic reaction is shown below.

$\left(Z\right){\text{-CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{CH}=\text{CH}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}{\text{COOCH}}_{\text{2}}{\text{CH}}_{\text{3}}+{\text{H}}_{\text{2}}\stackrel{\text{Pt}}{\to }$

The given reaction is the hydrogenation of alkenes in the presence of a platinum catalyst that reducesalkenes to alkanes. The principal organic product of the given reaction is shown below.

${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{CH}=\text{CH}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}{\text{COOCH}}_{\text{2}}{\text{CH}}_{\text{3}}+{\text{H}}_{\text{2}}\stackrel{\text{Pt}}{\to }{\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}{\text{CH}}_2-{\text{CH}}_2{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}{\text{COOCH}}_{\text{2}}{\text{CH}}_{\text{3}}$

d) The given organic reaction is shown below.

The carboxylic acid and its derivatives are reduced to the primary alcohol with the help of strong reducing agents such as lithium aluminum hydride, ${\text{LiAlH}}_{\text{4}}$, that has the ability to provide a hydride ion. In the given reaction, ${\text{LiAlH}}_{\text{4}}$ reduces only the $-\text{COO}$ group and has no effect on $\text{C}=\text{C}$ double bond. The principal organic product of the given reaction is shown below.

e) The given organic reaction is shown below.

$\left(Z\right){\text{-CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{CH}=\text{CH}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{COOH}+{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOOH}\to$

In the given reaction, the epoxidation of alkene takes place. In such a reaction, the transfer of an oxygen atom from the peracid to $\text{C}=\text{C}$ double bond of an alkene taken place that results in the formation of an oxirane ring. The principal organic product of the given reaction is shown below.

f) The given organic reaction is shown below.

$\text{Product of part(e)}+{\text{H}}_{\text{3}}{\text{O}}^{+}\to$

In the given reaction, the hydrolysis of the product takes place that results in the breaking of the oxirane ring and forms a vicinal diol that is associated with two hydroxyl groups present on adjacent carbon atoms. The principal organic product of the given reaction is shown below.

g) The given organic reaction is shown below.

$\left(Z\right){\text{-CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{CH}=\text{CH}{\left({\text{CH}}_{\text{2}}\right)}_{\text{7}}\text{COOH}\underset{\text{2}{\text{. H}}^{+}}{\overset{\text{1}{\text{. OsO}}_4\text{, }{\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}{\text{COOH, HO}}^{-}}{\to }}$

In the given reaction, osmium tetraoxide $\left({\text{OsO}}_{\text{4}}\right)$ is used to convert the alkene into $\text{1,2-}$ syn diols (vicinal diols). The principal organic product of the given reaction is shown below.

h) The given organic reaction is shown below.

In the given reaction, hydroboration of alkenes takes place with the help of ${\text{B}}_2{\text{H}}_6$ in presence of diglyme, ${\text{H}}_2{\text{O}}_2$ and ${\text{OH}}^{-}$ respectively. The hydroboration of alkenes results in the formation of alcohols. The addition of oxygen occurs at a less substituted carbon atom according to anti-Markovnikov rule. The principal organic product of the given reaction is shown below.

i) The given organic reaction is shown below.

In the given reaction, hydroboration of alkenes taken place with the help of ${\text{B}}_2{\text{H}}_6$ in presence of diglyme, ${\text{H}}_2{\text{O}}_2$ and ${\text{OH}}^{-}$ respectively. The hydroboration of alkenes results in the formation of alcohols. The addition of oxygen occurs at the less substituted carbon atom according to anti-Markovnikov rule. The principal organic product of the given reaction is shown below.

j) The given organic reaction is shown below.

In the given reaction, the dehydration of secondary alcohol is taken place in the presence of $\text{HCl}$ and results in the formation of alkene Also, on further addition of ${\text{H}}_{\text{2}}\text{O}$ the methoxy groups are also converted to alcohol groups. The principal organic product of the given reaction with molecular formula ${\text{C}}_{\text{21}}{\text{H}}_{\text{34}}{\text{O}}_{\text{2}}$ is shown below.