Q95 · CSIR NET Chemistry, June 2011
Paper: CSIR NET June 2011 · Subject: Organic Chemistry · Chapter: Pericyclic Reactions · Topic: Cycloaddition Diels Alder · Marks: 2 · Difficulty: Medium
The concerted photochemcial reaction between two olefins leading to a cyclobutane ring is :
(a)$\pi 2 \mathrm{s}+\pi 2 \mathrm{a}$ cycloaddition
(b)$\pi 2 \mathrm{~s}+\pi 2 \mathrm{~s}$ cycloaddition
(c)$\sigma 2 \mathrm{s}+\sigma 2 \mathrm{s}$ cycloaddition
(d)$\pi 2 \mathrm{~s}+\sigma 2 \mathrm{a}$ cycloaddition
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
A photochemical [2+2] cycloaddition of two alkenes is suprafacial on both components: π2s + π2s (b).
Study loop for Pericyclic Reactions