Massachusetts Institute of Technology
5.13: O rganic Chemist ry II
Dr. Sarah A. Tabacco
Hour Exam # 4
D ecember 5, 2003
Printed N ame ________________________
Signature ___________________________
MIT ID # ___________________________
Recitation TA ________________________
General Instructions:
• This is a closed book exam. N o books, notes, or calculators allow ed . You
are allow ed to u se m olecu lar m od els.
• Make sure that your exam has 12 pages (includ ing cover, a blank page for
extra w ork, and a p eriod ic table).
• Write you r nam e on each p age.
• Write answ ers in the spaces p rovid ed . If you ru n out of room , use the blank
p age and indicate this for your grader.
• Show all of your w ork if you w ish to receive partial cred it.
• Read the instru ctions carefully, and bu d get your tim e.
• GOOD LUCK!!
1__________/ 5
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2__________/ 9
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3__________/ 12
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4__________/ 10
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5__________/ 10
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6__________/ 10
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7__________/ 10
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8__________/ 10
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9__________/ 12
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10_________/ 12
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Total___________
(out of 100 points)
1. (5 p oints, all or nothing) Please rank the follow ing species by carbocation stability.
(1 = most stable, 2 = least stable)
H
H
Me
H
H
Me
H
Me
Me
2. (3 p oints each, 9 p oints total) In the boxes, p lease p rovid e the reagents for the illustrated
transform ations. More than one step m ay be requ ired .
a)
O
O
O
b)
O
O
NH
c)
O
O
Name_______________
2
3. (2 points each, 12 points total) Please provid e the prod ucts of the follow ing reactions.
If no reaction is exp ected , w rite "N R".
a)
O
Ph
O
Me
Na OEt
Me
OEt
(1 e quiv)
b)
AlCl3
Me Me
Cl
Me
c)
e xce s s I2
O
Ph
e xce s s Na OH
Me
d)
O
O
Me
1. ca t. Na OH
2. Na OH, ²
H
e)
HO
HO
Me
Me
H2 S O 4
f)
O
Me
1. Na OEt
(1 e quiv)
O
Me
EtO
Ph
2. H+ workup
Me
Name_______________
3
4. (2 points each, 10 points total) Please provid e the reagents for the follow ing
transform ations. Be specific about quantities of reagents w here relevant.
a)
Me
Me
O
Me
H
Me
O
b)
O
O
O
OMe
c)
O
O
CO 2 Me
CO 2 Me
d)
Me Me
O
O
O
Me
Me O
Me
O
e)
HO
Me
NH2
Me
Me
O
Me
Name_______________
Me
Me
4
5. (10 p oints) Please provide a d etailed m echanism for the follow ing transform ation.
Show all arrow p u shing.
O
Me
OMe
Me
Me
1. Me MgBr
2. H3 O
Me
Me
Me
+
Name_______________
O
Me
5
6. (10 p oints) Please provide a d etailed m echanism for the follow ing transform ation.
Show all arrow p u shing.
Me Me
Me
Me
H3 O + , ²
O
H
H2 O
O
Me
Name_______________
H
Me
6
7. (10 points) Please provid e a d etailed m echanism for the follow ing transform ation.
Show all arrow pushing. H int: This mechanism is from problem set 6.
O
O
1. Na OMe , Me OH
O
2. H+ workup
Me O
Me
Name_______________
7
8. (10 p oints) Diastereom ers A and B p rovid e d ifferent prod u cts u p on d iazotization. Please
exp lain w hy only one p rod u ct is form ed selectively in each reaction. You r exp lanation
shou ld inclu d e a 3-dimensional m echanism for the form ation of each p rod u ct from the
corresp ond ing d iazoniu m salt.
OH
t-Bu
A
NH2
OH
t-Bu
B
NH2
OH
Na NO 2
HCl
t-Bu
t-Bu
O
OH
Na NO 2
HCl
N2
O
H
t-Bu
N2
Name_______________
t-Bu
8
9. (12 points) Please provid e a synthesis of the ind icated com pound . All of the carbon
atom s should be d erived from dimethyl malonate and alcohols containing three or few er
carbons. You w ill receive partial cred it for a com plete retrosynthesis.
O
MeO
O
O
Me O
O
Me
O
OMe
d imethyl malonate
Name_______________
R OH
alcohols containing
three or few er carbons
9
10. (12 points) Please provide a synthesis of the ind icated com pound . All of the
carbon atom s should be d erived from methyl acetate. You w ill receive partial
cred it for a com plete retrosynthesis.
Me
O
Me
O
O
Me
Me
OMe
methyl acetate
Name_______________
10