Practice Fourth Examination A
Chemistry S-20
Last Name:
First Name:
Section TF:
Section Time:
Tue AM
Tue PM
(circle one)
Important Notes:
1. This exam consists of 8 problems on 8 pages, plus this cover sheet, and one page 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 page will not be graded.
3. You are allowed to use a set of molecular models for this exam.
1
Chemistry S-20
Name:
1. Fill in each box with the single major organic product of the indicated transformation. Be sure to indicate
stereochemistry if it is relevant! If more than one product is possible, please provide only the single most
likely product.
O
1. MeOH, H+
2. MeMgBr
a)
OH
3. H+ wkup
O
O
1. H2O, H+
b)
O
NH2
2. pH 5,
O
1. H3O+
c)
2. H+,
O
O
1. SOCl2
2. EtZnBr
OH
d)
3. EtSH, H+
4. Raney Ni
Cl
2
Chemistry S-20
Name:
2. Each of the following transformations can be carried out in one to three steps. Fill in the reagents
required for each step. If a second step is not needed, please put an "X" through the second box.
O
O
1.
a)
O
2.
Cl
3.
Br
1.
b)
2.
3.
Ph
N
1.
c)
NH
2.
3.
d)
1.
2.
3.
O
Chemistry S-20
Name:
3. Provide a multistep synthesis for the desired product from the indicated starting material. You may use
any organic or inorganic reagents, but all of the carbon atoms from the starting material must end up in the
product. The best answer will require or six fewer steps. Please ignore stereochemistry.
Starting material:
OH
O
O
Desired product
_______ / 12
Chemistry S-20
4
Name:
4. Fill in each box with the starting material that would provide the product of the indicated transformation.
For full credit, you will need to use each of the reagents in a meaningful way. Pay attention to stereochemistry
where relevant.
1. PhMgBr
2. H+ wkup
a)
3. H2C-PPh3
1. Mg, Et2O
2.
O
O
b)
3. H+ wkup
4. Br2
Br
1. LiAlH4
2. H+wkup
N
c)
3. pH 5
O
OH
d)
1. EtLi
2. H+ wkup
5
Chemistry S-20
Name:
5. Consider the following questions.
a. Provide a complete curved-arrow mechanism for the following cyclization reaction.
O2N
NaH
OH
O2N
O
Br
CH3
CH3
b. The constitutional isomer below is unreactive when treated with NaH. Explain this observation, using
clearly drawn resonance structures where appropriate.
OH
O2N
NaH
No Reaction
Br
CH3
_______ / 12
6
Chemistry S-20
Name:
6. Provide a complete curved-arrow mechanism for the following transformation:
H3C
CH3
CH3
H3C
CH3
CH3
CH3
HNO3
+
H2SO4
H3C
CH3
CH3
NO2
CH3
_______ / 12
Chemistry S-20
7
Name:
7. Provide a multistep synthesis for the desired product from the indicated starting material. You may use
any inorganic reagents and any hydrocarbons containing 4 carbons or fewer. The correct answer will
require six or fewer steps.
Starting material:
Br
CH3
CH3
Desired product
_______ / 14
Chemistry S-20
Name:
. Provide a curved-arrow mechanism for all steps in the indicated transformation.
O
OMe
N
1. LiAlH4
2. H+ , heat
OMe
N
_