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1. (20 pts, 5 ea) Draw the structure, using line notation, for each of
the following
(a) 3R-bromo-5S(3,3-dibromobutyl)-9R-cyclopropyl-1-pentadecyne
(b) cis-1,3-dimethylcyclooctane
(c) E-1-bromo-2-chloro-1-hexene
(d) 3Z,5Z-nonadiene
ANSWER
2. (16 pts) Give a complete mechanism for the following reaction
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3. (21 pts, 1 ea) For each of the following, circle all correct answers.
Note that a penalty of -1/2 will be assessed for each
extra answer.
(a) Circle all molecules that are isomers of 1,2-dibromocyclohexane
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(b) Circle the gauche rotamer.
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(c) Circle the strongest acid.
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(d) Circle the most stable carbocation. Assume no rearrangement occurs.
Judge each structure as drawn.
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(e) Circle the nucleophile that reacts fastest with CH3I in THF.
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(f) Circle the conformation with the least A-strain. Assume each conformation
is 'frozen.'
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(g) Circle all molecules that have at least one atom having sp2 hybridization.
ANSWER
(h) If the specific rotation of a pure alkyl halide is +100 degrees and a
chemical reaction with NaI generates a new alkyl halide with a specific
rotation of 0 degrees. Circle the reaction description that best describes
this result.
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(i) Circle all molecules that are capable of hydrogen bonding.
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(j) Circle the molecule with the most Baeyer strain.
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(k) Circle all structures that are considered to be intermediates.
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(l) For a SN1 reaction, if the concentration of nucleophile is doubled, what
is the effect on the overall rate?
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(m) Circle all cis alkenes.
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(n) Circle all meso compounds.
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(o) Circle the reagent formed when chlorine reacts with water.
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(p) Circle the maximum number of stereoisomers possible for
2,3,4,4,7-pentachlorododecane.
ANSWER
4. (25 pts; 5 ea) Explain each of the following with a brief answer.
(a) Cyclopentene reacts with diatomic bromine to give the trans-dibromide.
ANSWER
(b) 1-bromobutane undergoes an SN2 reaction in water rather than an
SN1 reaction.
ANSWER
(c) 1,2-Dimethylcyclohexane has two equilibrating chair conformations that
are of equal energy
ANSWER
(d) The reaction of 2(S)-bromobutane + NaCN in ether gives a product that is
not racemic.
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(e) The reaction of propyne and water with an acid catalyst gives a ketone as
a product.
ANSWER
5. (15 pts) Determine the absolute configuration for all stereogenic centers in
the following molecules.
ANSWER
6. (18 pts; 3 ea) Draw six different structural (constitutional) isomers for
the formula C7H12. Give the IUPAC name for each one.
ANSWER
7. (8 pts) Draw the highest energy rotamer and on gauche rotamer for
2,3-dichloroethane
ANSWER
8. (11 pts) Draw the transition state that would be required for the S>sub>N2
reaction of 2-bromo-2-methylpropane and KI in diethyl ether.
Use this diagram to explain why this combination of reactants
gives no reaction under these conditions.
ANSWER
9. (10 pts) On the diagram provided, draw the highest energy chair conformation
for the molecule shown.
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ANSWER
10. (56 pts; 4 pts ea) Give the major product for each of the following
reactions. If there is no reaction, indicate by
N.R. Remember stereochemistry where it is
appropriate.
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