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(CHEM111)[2001](s)quiz3~1463^_10038.pdf
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v3.1
Quiz #3, CHEM 111, Fall Semester, 2000/2001
Student Name: Student ID #: Section:
Note: You are required to complete all questions independently. Rreference materials are prohibited. Total marks for this quiz is 50 points.
Question 1: Draw the line-bond (Kekul) structures of the following molecules. (10 points)
(A) 2-Methyl-2-hexene (B) trans-2-Butene Answer:
(A) (B)
Question 2: Among the alkenes given below, which compound is the most stable? Give your reasoning. (10 points)
H3C
H3C
CH3H3C

H3C CH3H3C
(C) (D) (E)
Answer:
Question 3: The isobutyl cation (F) spontaneously rearranges to the tert-butyl cation (G) by a hydride shift. Draw an energy diagram for this reaction. According to the Hammond postulate, estimate whether the energy level of transition state is close to the reactant or the product. (10 points)
CH3

CH3
H3C C CH2 H3C
C CH3

H

(F) (G)
Answer:
(complete the energy diagram in the box provided below)


(Continue to reverse side for Question 4) v3.1
Question 4: Hydroboration of an alkene followed by oxidation (H2O2, OH-) is one of the useful method for alcohol synthesis. In order to synthesize the secondary alcohol (H) in an efficient way, what alkene structure you would suggest? Give your reasoning. (10 points)

OH
H2O
(H)
Answer: (fill the alkene structure in the box provided)
Question 5: In the radical chain polymerization process, a benzoyloxy radical adds to an unsymmetrical alkene to form the more stable radical such as (I). Hyperconjugation and inductive effect of the alkyl group (CH3) are used to account for the radical stability. Fill in the box provided below the structure of radical
(J) and give your reasoning. (10 points)


CH3 BzO


BzO + H2C C CH3
H
(I)
BzO

+ H2C C
H


(J)
Answer:
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