Q53 · CSIR NET Chemistry, June 2016
Paper: CSIR NET June 2016 · Subject: Organic Chemistry · Chapter: Pericyclic Reactions · Topic: Pericyclic Reactions – General · Marks: 2 · Difficulty: Hard
The correct match for the reactions P-S with the names of cyclizations I-IV is Reactions: (P) 
(Q) 
(R) 
(S) 
$n\text{-}\mathrm{Bu_3SnH}$ 
$80^{\circ}\mathrm{C}$ 
Name of Cyclizations: (I) halocyclization (II) Nazarov cyclization (III) radical cyclization (IV) electrocyclization
(Q) (R) (S) $n\text{-}\mathrm{Bu_3SnH}$ $80^{\circ}\mathrm{C}$ Name of Cyclizations: (I) halocyclization (II) Nazarov cyclization (III) radical cyclization (IV) electrocyclization(a)P-IV; Q-I; R-II, S-II
(b)P-II; Q-I; R-IV; S-III
(c)P-IV; Q-II; R-III; S-I
(d)P-II; Q-I; R-III; S-IV
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
P is a Nazarov cyclisation of the divinyl ketone (II). Q is a halocyclisation to the THF (I). R is a photochemical electrocyclisation (IV). S is a 5-exo radical cyclisation (III) (b).
Study loop for Pericyclic Reactions