1. (10) Choose one of the following phrases to
describe the relationship between the members of each pair below. Write the phrase on the line below the
structures. Structural isomers, configurational
diastereomers, conformational diastereomers,
configurational enantiomers,
conformational enantiomers.
a.
__configurational diastereomers__
b.
conformational enantiomers
2. (6) Select two of the structures below
that could be separated at room
temperature on the basis of a physical property like solubility. Write their identifying letters on the lines
below.
A
or B or C and D
or E
3. (5) If the heat of combustion of heptane is 1150 kcal/mol and if 3,3-dimethylpentane is 2
kcal/mol more stable than heptane, what is the heat
of combustion of 3,3-dimethylpentane?
1148 kcal/mol
4. (10) What is the name of the compound below.
8-bromobicyclo[3.2.1]octane
5. (10) Draw the most stable conformation of
the following compound. Full credit will
not be awarded unless your structure clearly shows the conformation according
to accepted conventions.
6. (8) Circle the chiral
structures among the following. (If
there is a partially erased or ambiguous circle, it will be marked wrong.)
The second,
third and fourth structures are chiral. The first is achiral.
7. (16) Draw the major organic substitution
product(s) of the following reactions.
Show the stereochemistry in your product structures.
a.
b.
8. (6) Draw the organic elimination product
of the following reaction.
9. (12) In each case draw the structures of
the two reactants that would lead to the nucleophilic
substitution product shown.
a. Show the reactants needed to prepare:
b.
Show the reactants needed to prepare the following compound. Use only reagents that have no more than two
carbons.
10. (5) Suppose that only one halogen in the
following molecule is replaced by iodide under SN2 conditions (NaI in acetone).
Write the product of the reaction.
11a. (10) Using the curved arrow formalism, draw
an SN1 type of mechanism (with the same first step as the SN1
mechanism) for the reaction below.
Clearly show the structure of the intermediate.
b. (2)
The compound shown above (compound A) reacts faster by an SN1
mechanism than its analogue below without a double bond (compound B) reacts by
an SN1 mechanism. Explain why
compound A reacts faster than compound B.
(Note that both are primary halides.)
The intermediate carbocation formed from compound A is resonance stabilized and therefore is formed faster than the very unstable primary carbocation formed from compound B.
From A from B