Name:
8:30 — 11:30 a.m.
1. This exam consists of 18 problems on 18 pages, plus this cover sheet, and two pages for scratch work at the end of the exam.
2. All answers must be written in the spaces provided.
Do not write anything in red ink.
Answers written on the back of a page will not be graded. Anything written on the scratch pages will not be graded.
3. You are allowed to use a set of molecuar models for this exam.
Problem
1.
4.
5.
2.
3.
6.
7.
8.
9.
Score
____________ / 16
____________ / 16
____________ / 16
____________ / 16
____________ / 18
____________ / 18
____________ / 18
____________ / 14
____________ / 14
Problem
10.
11.
12.
13.
14.
15.
16.
17.
18.
Score
____________ / 18
____________ / 18
____________ / 18
____________ / 18
____________ / 18
____________ / 16
____________ / 16
____________ / 16
____________ / 16
Total Score:
______________
/ 300

1 Name:
1. Each of the following transformations can be carried out in no more than three steps. Fill in the reagents required for each step. If a step is not needed, please put an "X" through that step.
a)
1.
2.
3.
OMe b)
O O
NH
2
1.
2.
3.
c)
1.
2.
3.
d)
O
1.
2.
3.
HO OH
_______ / 16

2 Name:
2. Each of the following transformations can be carried out in no more than three steps. Fill in the reagents required for each step. If a step is not needed, please put an "X" through that step.
a) OH
1.
2.
3.
b) OH
1.
2.
3.
c)
O
1.
2.
3.
d)
O
1.
2.
3.
O
N
H
O O
OEt
_______ / 16

a)
3
Name:
3. Fill in each box with the single major organic product of the indicated transformation. Be sure to indicate stereochemistry where relevant!
Cl
CH
3
KO t
Bu t
BuOH b) h c) EtO
O
O
OEt
1. NaOEt, EtOH
2. H
+ workup
3.
HS
4. Raney Ni
SH
, H
+ d) 1. Na
0
, liquid NH
3
2. Cl
2
, H
2
O
_______ / 16

a)
4
Name:
4. Fill in each box with the starting material of the indicated transformation. Be sure to indicate stereochemistry if it is relevant! For full credit, all reagents must be used in a meaningful way.
Cl
2
Cl
Ph Cl
H
CH
3
(+/-)
CH
3 b)
1. O
3
2. H
2
O
2
O
+
O
OH c) d)
1. DIBAL, 78 C
2. H
+ workup
3. CH
3
NH
2
, pH 5
N
CH
3
H
1. BH
3
, THF
2. NaOH, H
2
O
2
CH
3
OH
(+/-)
_______ / 16

5
Name:
5. Consider the following reaction sequence, ozonolysis of an alkene followed by reductive workup:
O
3 cycloaddition
O
O
O rearrangement
O
O
O
(CH
3
)
2
S
2
O
H
+
H
3
C
O
S
CH
3 a) Draw a complete Lewis structure of ozone, showing all formal charges and lone pairs. Then draw out all the molecular orbitals of ozone, clearly indicating which is the HOMO and which is the LUMO.
b) Your classmate suggests that ozone would react with dienes in a similar cycloaddition, as shown below.
Provide a complete curved-arrow mechanism for this proposed reaction.
O
O
O
O
O
O c) Using a frontier molecular orbital (FMO) argument, briefly explain why the reaction shown in part (b) would not be expected to proceed as shown.
_______ / 18

6
Name:
6. We continue our exploration of alkene ozonolysis followed by reduction. The key intermediate is the ozonide , highlighted below.
O
3 cycloaddition
O
O
O rearrangement
O
O
O
(CH
3
)
2
S dimethyl sulfide
2
O O
H
+
H
3
C
S
CH
3 ozonide a) The rearrangement to the ozonide occurs in two mechanistic steps as shown below. Draw a complete curvedarrow mechanism to account for this transformation, and fully classify any pericyclic reactions .
O
O
O
O
H
H
O
O
(rotate)
O H
H
O
O
O
O
O ozonide b) Identify the LUMO of the ozonide and the HOMO of dimethyl sulfide in the boxes provided below.
Ozonide LUMO: Dimethyl sulfide HOMO: c) Now draw a complete curved-arrow mechanism for the reduction of the ozonide with dimethyl sulfide.
_______ / 18

7
Name:
7. Upon treatment with the nitrosonium cation, compound A is transformed into compound B via the diazonium intermediate shown below.
CH
3
NO
CH
3
CH
3
H
3
C
S
CO
2
H
H
+
H
3
C
S
CO
2
H
H
2
O
H
3
C
S
CO
2
H
NH
2
Compound A
N
2
Diazonium intermediate
OH
Compound B a) Circle all of the stereogenic carbons in compound A above, and label each with the correct
R
/
S designation.
b) Draw a curved-arrow mechanism to account for both steps of the transformation of Compound A into
Compound B . Your mechanism must account for the observed stereochemistry to get full credit!
_______ / 18

8
Name:
8. You have just synthesized a new compound, and the following spectroscopic data are obtained:
• From the mass spectrum, you deduce that the molecular formula is: C
4
• The infrared spectrum is:
H
7
ClO
2 .
From the infrared spectrum, circle the functional groups that are definitely present:
O H C O C C C N
From the infrared spectrum, circle the functional groups that are definitely absent:
O H C O C C C N
• The proton NMR spectrum is:
3H
3H
1H
Draw your best choice for the structure of this molecule in the box below.
_______ / 14

9
Name:
9. You have just synthesized a new compound, and the following spectroscopic data are obtained:
• From the mass spectrum, you deduce that the molecular formula is: C
10
H
14
O .
• The infrared spectrum is:
From the infrared spectrum, circle the functional groups that are definitely present:
O H C O C C C N
From the infrared spectrum, circle the functional groups that are definitely absent:
O H C O C C C N
• The proton NMR spectrum is:
9H
2H 2H
1H
Draw your best choice for the structure of this molecule in the box below.
_______ / 14

10
Name:
10. Provide a complete curved-arrow mechanism for the following transformation, a variant of the classic
Beckmann rearrangement.
OH
N TsCl, pyr
H
N
H
2
O
O
You may represent TsCl as:
Ar
O O
S
Cl
_______ / 18

11
Name:
11. The following transformation occurs when the dichloro ether below is treated with benzene and aluminum trichloride.
OMe
OMe
Cl Cl
Cl
AlCl
3
Compound X a) Provide a curved-arrow mechanism to account for the formation of Compound X as shown above.
b) Compound X reacts rapidly with water via an S
N
1-type reaction, as shown below. Provide a curved-arrow mechanism for the reaction of Compound X to give the products shown. Be sure that your mechanism illustrates why this S
N
1 reaction is so rapid!
OMe O
Cl
H
2
O
H + MeOH + HCl
Compound X
_______ / 18

12
Name:
12. Provide a complete mechanism for the following multistep transformation. Use the curved-arrow formalism for each step.
O
Br O
Br
O
NaNH
2
(3 equiv.)
Na C C O
1.
O + liq. NH
3
2. excess TFA
(dry H
+
)
_______ / 18

13
Name:
13. Provide a complete curved-arrow mechanism for both steps of the following transformation.
O
O MeO O
1. NaOMe, MeOH
+ O OMe +
2. H
+ workup
Ph
OMe O
Ph
O
CO
2
Me
MeO
O
OMe
_______ / 18

14
Name:
14. Provide a complete curved-arrow mechanism for the following transformation. Please note that although thiamine is used in this transformation, this process takes place in the lab .
No enzymes are involved .
O
O
2
Ph H
NaOH, H
2
O
R
H
N
Ph
OH
Ph
S
(thiamine)
_______ / 18

15
Name:
15. Provide a multistep synthesis for the desired product from the indicated starting material, any inorganic reagents, and any organic reagents containing only one carbon . The best answer will require nine or fewer steps.
Starting material: plus any organic reagents containing one carbon
O
O
Desired product
_______ / 16

16
Name:
16. Provide a multistep synthesis for the desired product from the indicated starting material. You may use any inorganic or organic reagents, but all carbons from the starting material must end up in the product. The best answer will require eight or fewer steps.
Starting material:
O plus any organic compounds containing three or fewer carbons
NH
2
Desired product (+/–)
_______ / 16

17
Name:
17. Provide a multistep synthesis for the desired product from the indicated starting material. You may use any inorganic reagents and any organic compounds with two or fewer carbons . The best answer will require six or fewer steps.
Starting material: plus any organic compounds with two or fewer carbons
O
O
(+/-)
Desired product
_______ / 16

18
Name:
18. Provide a multistep synthesis for the desired product from the indicated starting material. You may use any inorganic reagents and any organic compounds with four or fewer carbons . The best answer will require five or fewer steps.
Starting material: plus any organic compounds with four or fewer carbons
O CN
CN
(+/-)
Desired product
_______ / 16

SCRATCH PAPER ONLY - NOTHING ON THIS SHEET WILL BE GRADED

SCRATCH PAPER ONLY - NOTHING ON THIS SHEET WILL BE GRADED