Q60 · CSIR NET Chemistry, June 2014
Paper: CSIR NET June 2014 · Subject: Organic Chemistry · Chapter: Photochemical Reactions · Topic: Photocycloaddition · Marks: 2 · Difficulty: Medium
The major product formed in the following photochemical reaction is 
(a)
(b)
(c)
(d)
Answer
Answer: A ✓ checked by 4AB · confidence medium
Explanation
Irradiation of 1,2,4-tri-tert-butylbenzene gives the valence isomer 1,2,5-tri-tert-butyl Dewar benzene. The bulky groups end up so as to relieve the ortho tBu/tBu strain (a).
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