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JEE Advanced · 2020 · 27 Sep 2020 · Paper 1 · General Organic Chemistry

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In the following reaction, compound Q is obtained from compound P via an ionic intermediate

What is the degree of unsaturation of Q?

Answer: 18

Solution

The reaction shows a Wagner-Meerwein rearrangement followed by cyclization. Analyzing the structure of Q from the reaction scheme:

Q is a polycyclic aromatic compound. Counting the structural features:
  • Multiple benzene rings (each contributes 4 degrees of unsaturation)
  • Additional rings and double bonds

Degree of unsaturation formula:

From the structure of Q shown in the solution, the total degree of unsaturation = 18.

JEE Advanced · 2020 · 27 Sep 2020 · Paper 1 · Numerical answer

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