Two aliphatic aldehydes $P$ and $Q$ react in the presence of aqueous $\mathrm{K}_2 \mathrm{CO}_3$ to

Question

Two aliphatic aldehydes $P$ and $Q$ react in the presence of aqueous $\mathrm{K}_2 \mathrm{CO}_3$ to give compound $R$, which upon treatment with HCN provides compound $S$. On acidification and heating, $S$ gives the product shown below:

Professor PC Thomas Classes · Answer

See detailed solution for explanation.