ADVANCED ORGANIC CHEMISTRY EXAMINATION: COMPREHENSIVE PERICYCLIC REACTIONS STUDY GUIDE

ADVANCED ORGANIC CHEMISTRY EXAMINATION:
COMPREHENSIVE PERICYCLIC REACTIONS STUDY
GUIDE




SECTION A: MULTIPLE CHOICE QUESTIONS (20 Marks)

Instructions: Select the single best answer for each question.



The Diels-Alder reaction is classified as which type of pericyclic reaction?

(A) A cycloaddition

(B) An electrocyclic reaction

(C) A sigmatropic rearrangement

(D) A group transfer reaction



Answer: (A)



According to the Woodward-Hoffmann rules, the thermal cyclization of 1,3,5-hexatriene
proceeds via which mode?

(A) Disrotatory

(B) Conrotatory

(C) Suprafacial

(D) Antarafacial

, Answer: (B)



Which of the following statements is true for a photochemical [2+2] cycloaddition?

(A) It proceeds suprafacially on both components.

(B) It proceeds antarafacially on both components.

(C) It is forbidden by the Woodward-Hoffmann rules.

(D) It forms a four-membered ring with retention of stereochemistry.



Answer: (A)



A [1,5] sigmatropic shift of hydrogen in a 1,3-pentadiene system is allowed thermally if it
proceeds through a:

(A) Suprafacial shift with a 4n electron system

(B) Antarafacial shift with a 4n electron system

(C) Suprafacial shift with a 4n+2 electron system

(D) Antarafacial shift with a 4n+2 electron system



Answer: (C)



The Cope rearrangement is a:

(A) [1,3] sigmatropic rearrangement

(B) [1,5] sigmatropic rearrangement

(C) [3,3] sigmatropic rearrangement

(D) [2,2] cycloaddition



Answer: (C)