Download Organic Chemistry Exam: Electrophilic, Nucleophilic Reactions, Spectroscopy, and Synthesis and more Exams Organic Chemistry in PDF only on Docsity!
Chem 2201
Fall 2024
Exam
1. Provide the name for the following (don’t forget E/Z and R/S assignments).
e. Draw the structure of pyridine.
2. A. Define electrophile:
Electrophile means electron loving species. They are electron deficient species attracted to electron rich
center and accepts electron from them.
I. Give an organic molecule that has a charge and reacts as an electrophile.
CH
3
-CH
2
carbocation
II. Give an organic molecule that has no charge and reacts as an electrophile.
The carbon of carbonyl
III. Give an organic molecule that has no charge and reacts as a Lowry Bronsted acid. Show an
example or explain why not.
Acetone. Strong base could abstract α-proton and carbon of carbonyl is electrophilic in
nature.
B. Define nucleophile:
Nucleophile means nucleus loving species. They are electron rich species and donate pair of
electrons to electrophiles.
I. Give an organic molecule that has a charge and reacts as a nucleophile.
-OH
, hydroxide has negative charge and acts as nucleophile
II. Give an organic molecule that has no charge and reacts as a nucleophile.
Ammonia (NH
3
) has no charge but a lone pair to act as nucleophile.
III. Give an organic molecule that has no charge and reacts as a Lowry Bronsted base. Show an
example or explain why not.
Ammines are nucleophile as they donate lone pair but they also act as Lowry Bronsted base as
they accept proton and gain positive charge.
3. Predict the major product for given reactions. Indicate stereochemistry if required.
5. Let's say you have a bottle of(R)-2-butanol and you want (R)- N,N -dimethyl-2-butanamine.Draw(R)-2-
butanol and(R)-N,N-dimethyl-2-butanamine.Show the reactions (it will require more than one
reaction)you would use to convert(R)-2-butanol into the desired amine. Assume you have any
alcohols, solvents, and inorganic reagents that you might need for the conversion. If any of your
reactions lead to mixtures, you must show all of the products. It's best to avoid mixtures.
6. Predict the spectrum (chemical shift & coupling) for the compound shown. Label your hydrogens so
that it is clear which signal goes with which hydrogen(s). You do not need to indicate the integration.
Show your work!
H δ coupling
a 0.9-1 ppm doublet
b 2.7 ppm multiplet
c 3.4 ppm singlet
d 7.1ppm doublet
E 6.8 ppm doublet
f 3.8 ppm singlet
7. Determine a structure for compound C, whose NMR is shown below. The formula for C is C
6
H
13
Cl.
The IR has a band at 2950 cm
. Assign the NMR signals to the structure you are proposing (i.e. label
your hydrogens in your answer and indicate the corresponding label on the spectrum or on a chart).
Score__
(24 pts) 3. Predict the major product for each reaction. Indicate the stereochemistry where relevant.
a.
b.
c.
d.
e.
f.
g.
h.
OTs
NaN
3
THF
OCH
3
NaOCH
3
Br
HOCH
3
Br
HOCH 3
low heat
NH
2
Br
THF
Cl Cl
CH
3
OH
heat
H
3
C
I
H
3
C
NaOCH
3
HOCH
3
H
3
C
CH
3
CH
3
catalytic
heat
OH
H
2
SO
4
Br
NaOCH
3
HOCH
3
heat
D
H
(1 7 pts) 4. Show the order of acidity for the following molecules: CH 3 CH 2 CH 3 , PhOH, CH 3 CH 2 NH 2 , CH 3 CH 2 OH,
CH
3
CO
2
H, HCl, and propyne. Draw the corresponding conjugate bases below each of the molecules in your list.
Most acidic Least acidic
Acidity:
Conjugate
Bases:
Draw the strongest organic acid (a molecule that only has carbon and hydrogen) we have encountered in class this
semester? (Hint: it isn’t very stable and it isn’t on this list.)
Draw the strongest organic base (a molecule that only has carbon and hydrogen) we have encountered in class this
semester? (Hint: it isn’t very stable either.)
How could you make your strongest organic base?
( 13 pts) 5. The molecule t - butyl methyl ether is an additive to gasoline. Having t - butyl methyl ether in the gas tank
improves the efficiency of combustion in a car engine. Let’s say you have t - butyl alcohol, methanol, PBr 3
, NaH, an
old battery (source of H 2 SO 4 ), window cleaner (source of ammonia), CO 2 (in the air), and THF in your garage. Let’s
also say you have an old car and you want to make sure it passes the emissions test, so you plan on adding t - butyl
methyl ether into the gas tank. Draw t - butyl methyl ether. Show how you would make t - butyl methyl ether using
only the chemicals in your garage. You probably won’t need to use all the chemicals. If any of your proposed
reactions give more than one product, then be sure to show all expected organic products.
t - butyl methyl ether:
synthesis of t - butyl methyl ether:
