Q92 · CSIR NET Chemistry, December 2015
Paper: CSIR NET December 2015 · Subject: Organic Chemistry · Chapter: Photochemical Reactions · Topic: Photocycloaddition · Marks: 2 · Difficulty: Hard
The correct statement about the following reaction is that 
(A)
(A)(a)$\mathrm{A}=$ 
and the reaction proceeds through carbene intermediate
and the reaction proceeds through carbene intermediate(b)$\mathrm{A}=$ 
and the reaction proceeds through nitrene intermediate.
and the reaction proceeds through nitrene intermediate.(c)$\mathrm{A}=$ 
and the reaction proceeds through Norrish type II path.
and the reaction proceeds through Norrish type II path.(d)$\mathrm{A}=$ 
and the reaction proceeds through Norrish type I path.
and the reaction proceeds through Norrish type I path.Answer
Answer: A ✓ checked by 4AB · confidence medium
Explanation
Photolysis of the α-diazoketone expels N₂ and gives a carbene. Wolff rearrangement then forms a ketene with ring contraction, and MeOH traps it as the methyl ester of the bicyclo[2.1.1]hexane: carbene pathway (a).
Study loop for Photochemical Reactions