Question

Draw the structure of the product of each step in the following three-step synthesis. Show the formal charges, if applicable. As a start, the benzene ring is drawn for you in each product. Although the first step produces a mixture of isomers, the para isomer is isolated as the sole product of interest and used in the second step. Give only the major product for the second and third steps.

Please help fill in the question marks with structures because my answer was wrong.

Answer 1

Concepts and reason

The concept used to solve this problem is based on electrophilic substitution reactions.

In electrophilic substitution reactions, a functional group is displaced by an electrophile.

Fundamentals

Substitution reactions are defined as reactions in which one functional group in the compound is replaced by another functional group. This substitution is called either electrophilic or nucleophilic depending upon the reagent used in the reaction.

(1)

The Lewis acid ${\rm{FeB}}{{\rm{r}}_3}$ reacts with ${\rm{B}}{{\rm{r}}_{\rm{2}}}$ as follows:

${\rm{FeB}}{{\rm{r}}_{\rm{3}}} + {\rm{B}}{{\rm{r}}_{\rm{2}}} \to {\rm{B}}{{\rm{r}}^ + } + {\rm{FeBr}}_4^ -$

Further, the reaction of electrophile with benzene ring is as follows:

(1)

The electrophile is generated by the reaction as follows:

${\rm{HN}}{{\rm{O}}_3} + {{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4} \to {\rm{NO}}_2^ + + {{\rm{H}}_2}{\rm{O}} + {\rm{HSO}}_4^ -$

Now, p-bromotoulene undergoes nitration as follows:

(2)

The further bromination reaction is written as follows:

Ans: Part 1

The correct major product for second step is as follows:

Part 2

The correct major product for third step is as follows:

Answer 2

(para-bromo toluene) +HNO3/H2SO4= (4-bromo-2-nitrotoluene)+Br2/FeBr3= 2,4-dibromo-6-nitrotoluene

Answer 3