Draw the structures in Fig. 5.1 for the organic products that could form in the three reactions shown.
Complete Table 5.1 by filling in the missing entries.
When methylbenzene reacts with an electrophile, substitution occurs. No addition reaction happens under these conditions. Explain why addition is not observed.
The reaction of methylbenzene with $\text{SOBr}_2$ in the presence of an iron(III) bromide catalyst, $\text{FeBr}_3$, is shown in Fig. 5.2. This reaction follows the same mechanism as the bromination of benzene. The first stage of the mechanism forms the $\text{SOBr}^+$ electrophile, as shown. $\text{SOBr}_2 + \text{FeBr}_3 \rightarrow \text{SOBr}^+ + \text{FeBr}_4^-$ The reaction of methylbenzene with $\text{SOBr}^+$ ions is shown in Fig. 5.3. Complete the mechanism in Fig. 5.3. Include all relevant curly arrows and charges. Draw the structure of the organic intermediate.
The reaction shown in Fig. 5.2 produces a small amount of a by-product, P, with the molecular formula $\text{C}_{14}\text{H}_{14}\text{OS}$. Suggest a structure for by-product P.
Acyl bromides, RCOBr, can be prepared by reacting a carboxylic acid with $\text{SOBr}_2$. This is analogous to the preparation of acyl chlorides using $\text{SOCl}_2$. Give an equation for the reaction between ethanoic acid and $\text{SOBr}_2$.
Suggest the relative ease of hydrolysis of acyl bromides, RCOBr, acyl chlorides, RCOCl, and alkyl chlorides, RCl. Explain your answer.
The reaction shown in Fig. 5.2 produces a small amount of a by-product, $P$, with the molecular formula $\text{C}_{14}\text{H}_{14}\text{O}\text{S}$. Suggest a structure for by-product $P$.