Chemistry 331 - Winter 1996
Elements of Organic Chemistry I

Professor Carl C. Wamser

EXAM 1
February 6, 1996

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1. (12 points) Write a complete IUPAC name for each of the following compounds, including designation of stereochemistry if it is specifically shown:

2. (20 points) Write accurate structures for each of the following names:

a) isobutylcyclobutane

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b) cis-1-bromo-3-methylcyclopentane

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c) the chair structure for the most stable conformer of tert-butylcyclohexane

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d) a Newman diagram for the most stable conformer of 1-bromopropane

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e) (Z)-4,6-dimethyl-3-heptene

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3. (10 points) For the compound shown below:

Write the molecular formula (i.e., CxHy.... ).

Identify each carbon atom as 1°, 2°, 3°, or 4°.

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4. (10 points) For the compound shown below:

Write the molecular formula.

Identify the expected hybridization of each carbon atom.

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5. (15 points) Predict whether the following reactions would be expected to have a more favorable equilibrium to the right or to the left.

a) CH3OH + NaNH2 <====> CH3ONa + NH3
pKa = 16 pKa = 33

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b) CH3OH + HI <====> CH3I + H2O
delta H = - 13 kcal/mole
Ea = 15 kcal/mole

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Write as much as you can of a potential energy diagram for the second reaction.
Clearly label what the x and y axes represent, the location of the reactants and the products, and where delta H and Ea would be measured.
Explain what additional information would be needed to make it complete.

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6. (15 points) The structures shown below are meant to be the two chair conformations of the same compound. Properly locate the two missing substituents on the conformation on the right.



If delta H = - 1.3 kcal/mole for the equilibrium as shown, explain what information this tells you about the relative interactions between methyl and chloro substituents.

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7. (18 points) Rewrite each of the reactions shown below, providing more detailed structures that clearly show the following:
Identify the bonds that are broken.
Identify the new bonds that are made.
Identify which reactant acted as a nucleophile and which as an electrophile.

CH2=O + CH3Li -----> CH3CH2O- Li+

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CH3NH2 + CH3I -----> (CH3)2NH2+ I-

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Select either of the two reactions and explain why the reactants have the properties of a nucleophile or electrophile.