Pericyclic Reaction MCQ Questions for CSIR NET - Download PDF of assigment on www.ChemistryABC.com

Pericyclic Reaction MCQ Questions for CSIR NET. 

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) π²_s + π²_a 

(b) π²_s + π²_s 

(c) σ²_s + σ²_a 

(d) π²_s + σ²_a 

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.

Ans Key:

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