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Chemistry 331: Objectives
for Exam 2
Go to a summary
listing of reactions for Exam 2
You should be able to:
- Nomenclature: Given a
structure write the IUPAC name, or given an IUPAC name
draw the structure, for any alcohol, alkyl halide, or
alkene (including E-Z designation).
Radicofunctional nomenclature will not be emphasized.
[4.1, 4.2, 5.1, 5.3, 5.4]
- Structure-Property Relationships:
Predict relative boiling points, solubilities, and
stabilities (heats of combustion and hydrogenation) for
alcohols, alkyl halides, and alkenes. Know how to predict
differences in thermodynamic stabilities of the different
types of substituted alkenes. [4.5, 5.5] Recognize the
different classes of alkyl halides and alcohols. [4.3]
- Mechanisms (Note that mechanisms are very
important.)
- Write out the steps for the
acid-catalyzed SN1 and SN2
mechanisms for reactions of alcohols and predict the
relative reactivities of alcohols toward these
mechanisms. Use curved arrows. [4.10-4.14]
- Write out the steps for the mechanism for
free-radical halogenation of alkanes and predict the
number of monohalogenated products and relative
product distributions in the halogenation of higher
alkanes. [4.16-4.20]
- Write out the steps for the E1 mechanism for the
acid-catalyzed dehydration of alcohols and explain
regiochemistry, stereochemistry, and rearrangements in
terms of the mechanism. Use curved arrows. [5.10-5.13]
- Diagram the E1 and E2 mechanisms for the
dehydrohalogenation of alkyl halides and explain the
regiochemistry and stereochemistry of the reactions.
[5.14-5.17] (The E2 mechanism is more important than
the E1 mechanism for alkyl halide eliminations.) Use
curved arrows. Note the anti-periplanar orientation
needed for the E2 reaction.
- Explain regioselectivity and stereoselectivity in
electrophilic and free-radical additions to alkenes.
[6.6-6.8, 6.15-6.16] (The step-by-step mechanism of
peroxide catalyzed addition of HBr to alkenes is not
covered for Exam 2.)
- Show the mechanism of addition of HX to alkenes,
which proceeds by a carbocation intermediate. Be aware
of situations where carbocations may rearrange. Use
curved arrows.
- Write the mechanism of addition of Br2
and Cl2 to alkenes. Know that the important
intermediate is a bridged halonium ion (3-membered
ring). For halohydrin formation, the mechanism is
similar to halogenation except that the halonium ion
is attacked by water instead of a halide ion. Both
reactions proceed via anti addition. Use curved
arrows.
- Although the mechanism of hydroboration-oxidation
is not covered on Exam 2, you should know that the
reaction gives syn addition of water to an
alkene and that the addition has anti-Markovnikov
regiochemistry.
- Reactions: (Categorize these according to
type of mechanism.)
- Reactions of alcohols
- alkyl halides from alcohols and
hydrogen halides [4.9]
- other methods for converting alcohols to alkyl
halides [4.15]
- Free-radical halogenation of alkanes [4.20]
- Preparation of alkenes
- dehydration of alcohols [5.9-5.11]
- dehydrohalogenation of alkyl halides [5.14]
- Reactions of alkenes
- hydrogenation (syn addition of
H2) [6.1]
- addition of hydrogen halides [6.4]
(Markovnikov)
- addition of HBr and peroxides [6.8]
(anti-Markovnikov)
- addition of sulfuric acid and then water [6.9]
- hydration using sulfuric acid and water [6.10]
- hydroboration-oxidation (syn addition of
H2O)[6.11]
- addition of halogens (anti addition of
X2)[6.14]
- halohydrin formation (anti addition of
HOX) [6.17]
- epoxidation [6.18]
- ozonolysis [6.19]
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of Colorado at Colorado Springs
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