Carboxylic Acids and their Derivatives 2 Question 35
35. Identify $X$ and $Y$ in the following synthetic scheme and write their structures. Explain the formation of labelled formaldehyde $\left(\mathrm{H}_{2} \stackrel{}{\mathrm{C}} \mathrm{O}\right)$ as one of the products when compound $(Z)$ is treated with $\mathrm{HBr}$ and subsequently ozonolysed. Mark the $\mathrm{C}^{}$ carbon in the entire scheme.
$$ \begin{aligned} & \mathrm{Ba}^{\stackrel{}{\mathrm{C}} \mathrm{O}{3}}+\mathrm{H}{2} \mathrm{SO}_{4} \longrightarrow X \quad\left(\stackrel{}{\mathrm{C}}=\mathrm{C}^{14} \text { gas }\right) \ & \mathrm{CH}{2}=\mathrm{CH}-\mathrm{Br} \xrightarrow[\substack{\text { (ii) } X \ \text { (ii) } \mathrm{H}{3} \mathrm{O}^{+}}]{\text {(i) Mg/ether }} Y \xrightarrow{\mathrm{LiAlH}_{4}} Z \end{aligned} $$
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Solution:
- $\mathrm{H}{2} \mathrm{C}=\mathrm{CH}-\mathrm{Br} \xrightarrow[\text { (ii) } X]{\text { (i) } \mathrm{Mg} / \text { ether }} \mathrm{H}{2} \mathrm{C}=\underset{Y}{\mathrm{CH}} \underset{{ }^{*}}{\stackrel{\mathrm{O}}{\mathrm{C}}}-\mathrm{OH}$
$$ \text { (iii) } \mathrm{H}_{3} \mathrm{O}^{+} $$
$$ \mathrm{H}{2} \mathrm{C}=\mathrm{CH}-\stackrel{*}{\mathrm{C}} \mathrm{H}{2} \mathrm{OH} $$
