ORGANIC CHEMISTRY 301

EXAMINATION FOUR-JULY 1, 1996

I. (Five points each) Synthesize the following compounds:

c. 1,2-dichloro-1,2-diphenylethane from benzene, alkanes of three carbons

or less, and inorganics

II. (Three points each) Explain why the following compounds are aromatic or not aromatic:

III. (Four points each)

a. From a mechanistic viewpoint, what characteristic(s) must an activator have that separate them from deactivators in electrophilic aromatic substitution?

b. Why is the Kekule drawing, for benzene, both useful and misleading?

c. Does the following compound possess 24 pi electrons? Explain.

d. Explain how the resonance effect works in electrophilic aromatic substitution.

e. To convert benzene to cyclohexane, via hydrogenation, severe conditions are necessary. Why?

IV. (Fifteen points)

Compound A (C₉H₁₀)

A + Br₂/CCl₄ ® colorless

A + KMnO₄ ® brown ppt

low pressure

A + H₂/cat ® B (C₉H₁₂)

high pressure

A + excess H₂/cat ® C (C₉H₁₈)

A + HBr ® D

D + alc-KOH ® E + F

major

B + Br₂/FeBr₃ ® G + H

major

A + Br₂/FeBr₃ ® I + J

major

E + Br₂/FeBr₃ ® K

F + Br₂/FeBr₃ ® K

A + O₃/Zn,H⁺ ® L + M

A + O₃/H₂O₂ ® N + O

E + O₃/Zn,H⁺ ® P + Q

F + O₃/Zn,H⁺ ® P + Q

Identify A through Q.