This page contains one of the assignments related to MCQ Questions related to Pericyclic Reactions for CSIR NET & GATE Chemistry exam. You can download or read other assignments as well on our topic wise MCQ questions page.
Questions
Q1. The reaction given below is an example of
[NET June 2011]
(a) 1, 3-sigmatropic shift
(b) 1, 3- methyl shift
(c) 1, 5-sigmatropic shift
(d) 1, 5-methyl shift
Q2. The concerted photochemical reaction between two olefins leading to a cyclobutene ring is
[NET June 2011]
(a) π2s + π2a
(b) π2s + π2s
(c) σ2s + σ2a
(d) π2s + σ2a
Q3. The structures of major products X and Y in the following transformation are
[NET June 2011]
Q4. In the following concerted reaction, the product is formed by a
[NET Dec 2011]
(a) 6π disrotatory electrocyclization
(b) 4π disrotatory electrocyclization
(c) 6π conrotatory electrocyclization
(d) 4 π conrotatory electrocyclization
Q5. The major products A and B in the following reaction sequence are
[NET Dec 2011]
Q6. The major products A and B in the following reaction sequence are
[NET Dec 2011]
Q7. The major products A and B in the following reaction sequence are
[NET Dec 2011]
Q8. The product formed and the process involved in the following reaction are
[NET Dec 2011]
Q9. The major product formed in the following concerted reaction is
[NET June 2012]
(a)
(b)
(c)
(d)
Q10. The major product formed when (3R, 4S)-3, 4-dimethylhexa-1,5-diene is heated at 240º is
[NET June 2012]
(a) (2Z, 6Z)-octa-2,6-diene
(b) (2E, 6E)-octa-2,6-diene
(c) (2E, 6Z)-octa-2,6-diene
(d) (3Z, 5E)-octa-3,5-diene
Q11. In the following pericyclic reaction, the structure of the allene formed and its configuration are
[NET June 2012]
Q12. In the following reaction sequence of pericyclic reactions, X and Y are
[NET Dec 2012]
Q13. The following conversion involves
[NET Dec 2012]
(a) a 1, 3-dipolar species as reactive intermediate, and a cycloaddition.
(b) a carbenium ion as reactive intermediate, and a cycloaddition.
(c) a 1, 3-dipolar species as reactive intermediate, and an aza-Witting reaction.
(d) a carbanion as reactive intermediate, and an aza Cope rearrangement.
Q14. The following transformation involves
[NET Dec 2012]
(a) an iminium ion, [3, 3]-sigmatropic shift Mannich reaction.
(b) a nitrenium ion, [3, 3]-sigmatropic shift Michael reaction.
(c) an iminium ion, [1, 3]-sigmatropic shift Mannich reaction.
(d) a nitrenium ion, [1, 3]-sigmatropic shift Michael reaction.
Q15. The major product in the following reaction is
[NET Dec 2012]
Q16. With respect to the following biogenetic conversion of chorismic acid (A) to 4-hydroxyphenyl pyruvic acid (C), the correct statement is
[NET Dec 2012]
(a) X is Claisen Rearrangement; Y I oxidative decarboxylation.
(b) X is Fries rearrangement; Y is oxidative decarboxylation.
(c) X is Fries rearrangement; Y is dehydration.
(d) X is Claisen rearrangement; Y is dehydration.
Q17. Among the following dienes, the one that undergoes a degenerate Cope rearrangement is
[NET June 2013]
(a)
(b)
(c)
(d)
Q18. The major product formed in the following reaction is
[NET June 2013]
(a)
(b)
(c)
(d)
Q19. The major product formed in the following reaction is
[NET June 2013]
(a)
(b)
(c)
(d)
Q20. The most appropriate mode of cyclization in the following transformation is
[NET June 2013]
(a) Conrotatory in photochemical and disrotatory in thermal conditions.
(b) Conrotatory in thermal and disrotatory in photochemical conditions.
(c) Conrotatory in thermal and disrotatory in photochemical conditions.
(d) Conrotatory in photochemical and disrotatory in thermal conditions.
Solutions
Q1-c Q2-b Q3-c Q4-a Q5-d Q6-b Q7-b Q8-c Q9-a Q10-c Q11-a Q12-c Q13-a Q14-a Q15-c Q16-a Q17-a Q18-a Q19-c Q20-d