Question

CH$_2$(CO$_2$Me)$_2$ + $\xrightarrow[\text{NaOEt}]{\text{excess}}$ (P) $\xrightarrow[2. \text{ HCl, }\Delta]{1. \text{ aq NaOH}}$ (Q)

If number of $sp^3$ hybridised C-atoms in (Q) is x and degree of unsaturation of compound (Q) is y, then find the value of $[1 + \frac{x}{y}]$

Answer 1

3

Answer 2

The reaction sequence leads to cyclobutanecarboxylic acid (Q). The cyclobutane ring contains 4 $sp^3$ hybridized carbon atoms, so $x=4$. The molecule has one ring and one carbonyl group, giving a degree of unsaturation $y=2$. Therefore, $[1 + \frac{x}{y}] = [1 + \frac{4}{2}] = 3$.