Q25 · CSIR NET Chemistry, June 2011
Paper: CSIR NET June 2011 · Subject: Organic Chemistry · Chapter: Photochemical Reactions · Topic: Photocycloaddition · Marks: 2 · Difficulty: Medium
The concerted photochemical reaction between two olefins leading to a cyclobutane ring is:
(a)$\pi 2s + \pi 2a$ cycloaddition
(b)$\pi 2s + \pi 2s$ cycloaddition
(c)$\sigma 2s + \sigma 2s$ cycloaddition
(d)$\pi 2s + \sigma 2a$ cycloaddition
Answer
Answer (as printed): B
Explanation
HOMO of one alkene reacts with LUMO of other, LUMO HOMO HOMO Detailed Mechanism, CSIR DEC 2011
Explanation as extracted from the printed page; notation may be imperfect.
Study loop for Photochemical Reactions