Q75 · CSIR-NET Chemistry, December 2012
Paper: CSIR-NET December 2012 · Subject: Organic Chemistry · Chapter: Photochemical Reactions · Topic: Photocycloaddition · Marks: 2 · Difficulty: Medium
The following photochemical transformation proceeds through 
(a)Norrish type I reaction
(b)Norrish type II reaction
(c)Barton reaction
(d)Paterno-Buchi reaction
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
The excited ketone abstracts the γ-H (from N–CH₃), and the 1,4-biradical closes Yang-fashion to the azetidinol: Norrish type II (b).
Study loop for Photochemical Reactions