Fall 05 Organic I Final Exam
200pts (graded as 300pts)
Name
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1) (5pts total) Give one definition of a Nucleophile
b) Give one definition of an Electrophile
c) Give one definition of an acid.
2) (i) Briefly explain what is meant the following terms:(10pts total)
Organic Chemistry
Chiral Molecule
Racemic Mixture
Rate Determining Step
Anti Addition
2) (ii) Draw the corresponding cations that these molecules would form upon ionization.
(6pts)
Cl
Br
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3) Name the classes of compound that the following molecules belong to (E.g. alkane,
amide, etc). (15pts)
R O-R
R O-O-R
O
R
R O-H
O
O-H R
O
H
R
O-R
O
R
R
R
O
O
R
O-O-H
R
R
R
4) Draw Lewis structures (sticks for bonds, and dots for lone pairs) for the below two
molecules. (10pts)
OH
HO
O
5) For the previous two molecules, label the hybridization of all the carbons. (5pts)
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6) Classify each of the following reactions as an Elimination, Addition or Substitution.
(5pts)
(a)
OH
H3C
(b)
H3C
CH3
(c)
CH3
F
H Br
Ph
H
Ph
H
Ph
H
Br H
Ph
H Cl
H3C
(d)
H3C
CH3
CH3
Cl H
(e)
H3C CH2Br
H3C CH2OH
7) Explain why in this electrophilic addition reaction, none of product A is generated,
and product B is formed exclusively. (9pts)
Cl
H
H
CH3
(E & Z)
X
H-Cl
H-Cl
H
CH3
H
Cl
H
CH3
Product B
Product A
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8) Draw an energy level diagram for a typical endothermic SN1 process. Make sure to
label (a) the axes (b) the reactants and products (c) any transitions states (d) ΔHo for the
overall reaction (e) the rate determining step (9pts)
9) By considering the hybridization of the central atom, predict the shapes and bond
angles of CH3+ and H2O. (10pts)
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10)
Name the following molecules in IUPAC form. (16pts)
(a)
Cl
(b)
CH3CH2
H
CH2CH2Br
H
F
(c)
Cl
(d)
CH3
Cl
(e)
HO
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11) Assign R or S to each chiral center in these molecules. (12pts)
F
(a)
Cl
NH2
H3C
F
(b)
(c)
(d)
H3C
H
H
O
H
O
H
Cl
H3C
Cl
Cl
Cl
CO2H
H
H
CF2H
12) What is the name of the type of Projection used in part (d)? (2pts)
(b) Which three chemists invented the C-I-P priority convention used to assign R and S?
(2pts)
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13) Explain mechanistically the observation that when Br2 is added to cyclohexene, the
Bromine atoms end up anti to one another. (10pts)
Br-Br
Br
Br
anti dibromide
14) The most stable conformation for a cyclohexane ring bearing an ethyl group is a
“chair conformation with the ethyl group equatorial”.
(i)
Explain and draw what the chair conformation is (4pts)
(ii)
Explain what ‘equatorial’ is (2pts)
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15) Below shows a way to indirectly isomerize alcohols, in two steps.
i)
Provide the reagents to accomplish each step
ii)
What is the name of the regiochemistry of the addition step (8pts)
OH
OH
16) Answer the following:
(i) State two characteristics of an E1 reaction. (2pts)
(ii) State two characteristics of an SN2 reaction. (2pts)
(iii) Explain the difference between stereoisomers and structural isomers. Provide an
example of both types. (6pts)
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17) Give the reagents for 5 of the 6 following reactions of cyclohexene. (15pts)
Br
O
Cl
OH
Br
OH
OH
17b) Write the mechanism for one of the preceding reactions. (10pts)
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18) Give the products in 5 of the 6 following transformations. (15pts)
CF3CO2H, H+
PCC
1) Pyridine, Tos-Cl
2) NaSH
OH
1) NaOH
2) CH3CH2CH2Br
H2SO4
PBr3
18b) Write the mechanism for one of the preceding reactions. (10pts)
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Bonus Question (up to 5 points!)
Either list your favorite 5 things about organic chemistry (I) this semester.
or
Define these online gaming terms.
Modder
Noob
Camping
Weapon whore
Teabag
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