California State Polytechnic University, Pomona Chem 316 Midterm Exam Winter, 2014 Beauchamp
Name:__________________________________
Topic 1. Nomenclature (1)
Total Points Exam Points 30
2. Arrow-pushing Mechanism and Explanation
20
3. Reactions page 10 x 3 lines of reactions studied so far in organic chemistry 4. Tautomers (one in acid and one in base)
30
5.
14
C synthesis (methane, ethane, propane, cyclopentane, bromobenzene, NaCN, CO2, 14C compounds), protection 6. Bio-Organic Game (21 transformations) Total
Credit
30 30 6 40 180 186
This is a long exam. It has been designed so that no one question will make or break you. The best strategy is to work steadily throughout the period, starting with those problems you understand best. Make sure you show all of your work. In mechanism problems, draw in any lone pairs of electrons, formal charge and curved arrows to show electron movement. If resonance is present in a mechanism problem, draw at least one additional resonance structure to show you recognize this feature (make sure the “best” resonance structure is included in your two resonance structures). On synthesis and reaction problems, do not write mechanisms (unless you need to prompt yourself). You are only given credit for the correct product and/or reagents. Only write answers on the front of each page. Do your best to show me what you know in the time available.
To those who can dream, there is no such place as faraway.
California State Polytechnic University, Pomona 1. Provide an acceptable name for the following structure. (30 pts) 1 1
1
1
4
2
4
4
4 9S 7Z
O 1
3
3
2
H
12 10
3E
O
O 9
4 5
H
NH2
O 5
3 2 6 7
3
2
1 8
2
1
Br OH
3
8 1
2R
SH
1
11
1
3
3
4R
2
6
4
O
NH2
3
1
O
1
2
2
4
6 5
2Z 1
7 1
O
2
1 2
3
5S
3
4 4
1 5
1-propyl-3-bromo-4-benzyl-5-phenyl-6-mercaptohex-2Z-enyl (2R,4R,5S,9S)- 2-hydroxy-3(pen-3-ynyl)-4-amino-5-amido6,12-dioxo-8-(4-f ormylcyclooct-3E-enyl)-9-(1-ethyl-3-methylbutoxy)dodec-7Z-en-10-ynyl
2. Provide complete arrow-pushing mechanisms for the reactions below. Include curved arrows, lone pairs of electrons and formal charge. If resonance is important to your solution, draw the best resonance structure and one additional resonance structure to show you recognize this feature. Write the final structure and explain why it forms over any other possibility. Possible in 6 steps. (20 pts)
California State Polytechnic University, Pomona 3.
Provide the expected product for each of the following transformations. Show regiochemistry and stereochemistry clearly, if relevant. Do NOT show mechanisms. (30 pts)
a.
b.
c.
Br
d.
e.
f.
g.
h.
i.
j.
1. NaN3 2. LiAlH4 3. workup
O N NH2
pH=5,(-H2O)
1. NaH3BCN O 2. Cl
O N
California State Polytechnic University, Pomona 4. Propose a mechanism for the following tautomeric transformation in base and acid. (30 pts) a. (3 tautomeric changes)
b. (3 tautomeric changes)
California State Polytechnic University, Pomona 5. Propose a synthesis for the following compound using methane, ethane, propane, cyclohexane, sodium cyanide or carbon dioxide. Your only source of radioactive 14C carbon is 14C methane, *CH4, carbon dioxide, *CO2 and sodium cyanide, Na*CN. You may also use any typical organic reagents. Often the best strategy is to work backwards from the target molecule. The last step of the synthesis should be your first step. Show the reagents and reactant for each backwards step until you reach allowable starting molecules. Do not show mechanisms. (30 pts) available molecules
Br
NaCN *
* CH
CH4
*
NaCN
4
CO2
CO2
1. pH=5 (-H2O) 2. NaH3BCN 3. wk
target structure O
O H
*
*
N
O
N
Cl
NH2 SOCl2 O *
*
*
*
Br
3. wk
OH
1. NaN3 2. LiAlH4 3. wk Br
Br
*
H3C
*
CH4
*
*
*
1. Mg 2. O
*
*
Br h
OH 1. Mg 2. CO2 3. wk
HBr
1. Mg 2. O
Br *
*
3. wk HO
O
HBr OH
1. Mg 2. O
Br
Br
OH
H O 3. wk
1. Mg 2. O
HBr
3. wk
*
H3C
OH
O mCPBA
Br
Br h
Br
Br h
t-butoxide
O
t-butoxide
mCPBA
Br H3C
Br h
*
H
HBr
*
O
OH
*
H
CrO3 H2O
*
O
1. NaOH 2. Br
*
O
*
H3C
CH4
Propose a synthetic sequence of 3 steps or f ewer to accomplish the f ollowing transf ormations (6 pts). OH
THP
OH
OH
R3SiCl R3N
O O
TsOH OH HO TsOH (-H2O) O
O OR
O
O
1. LiAlH4 2. workup OR
SiR3
THP
R3Si
O
O
O
O
O
OH
O
OH
O
OH
H3O+ H2O
+
H3O H2O
California State Polytechnic University, Pomona 6. From the given bio-organic structure, use our simplistic mechanisms to show how each transformation could occur. If any structures are missing, use the descriptive term to fill in the necessary structures and details. Draw in any additional atoms or structures needed to demonstrate the transformations (e.g. a hydrogen atom or a water molecule, any co-factors, etc.). Use B: if you need a base and B-H if you need an acid. Acceptable representations of possible co-factors are provided below. (30 pts) Simplified co-factors for the bio-organic game problems, if needed.
a. H
H
B B
H OH
O
H
H
OH
R
N
B H
O
O
OH
B
O
OH
O H
H
H
H
OH
O
R
N
O
S
O
O B
H
OH
H
OH
OH
N
N
R B
OH
CH2
HO
H
O
HO
HO
HO
O
B
O
H
OH
O
S
H
B
N
B
H
H
R H
O
N
B
R
H
H
H OH
O OH
N
R B
B
H
S
N
B
R
HO
S
H
H
C O
O
OH
O
H
H O
S
O
H
R B
B
O
N
O
R
H
O N
OH
H
H H
H
H
O OH
H
OH B
B
R
N
R
N
R
H
OH
H
B
B
OH
B
O
H
O H R
H
H
N
O
O
O
N
O OH
B
O P
H
R
B OH
H
O
R N
OH
OH
California State Polytechnic University, Pomona b. O P
O O
O
H
CoA
ATP O
H
OH
O
O O
O
OH S
O B
O
H
P
HO
H
P
B
O
O
O HO
B
S
OH
O
HO
B
HO
O
O
CoA O
ADP B
O
O ATP
H
P
H
S
O H
O
B
duplicate structure
O P O
O
O
H
O
O
H
O
H O
B
O
O
H
O
H
H
HO
R
O O
O
O H
O
B H
C O
H
H
O
O
N N
N B
H
FADH2
N
N H
O P
O
R
CoA
O
FAD
Every problem has a gift for you in its hands.
Richard Bach
N
California State Polytechnic University, Pomona Chem 316 Midterm Exam Winter, 2014 Beauchamp
Name:__________________________________
Topic 7. Nomenclature (1)
Total Points Exam Points 30
8. Arrow-pushing Mechanism and Explanation
20
9. Reactions page 10 x 3 lines of reactions studied so far in organic chemistry 10. Tautomers (one in acid and one in base)
30
11.
14
C synthesis (methane, ethane, propane, cyclopentane, bromobenzene, NaCN, CO2, 14C compounds), protection 12. Bio-Organic Game (21 transformations) Total
Credit
30 30 6 40 180 186
This is a long exam. It has been designed so that no one question will make or break you. The best strategy is to work steadily throughout the period, starting with those problems you understand best. Make sure you show all of your work. In mechanism problems, draw in any lone pairs of electrons, formal charge and curved arrows to show electron movement. If resonance is present in a mechanism problem, draw at least one additional resonance structure to show you recognize this feature (make sure the “best” resonance structure is included in your two resonance structures). On synthesis and reaction problems, do not write mechanisms (unless you need to prompt yourself). You are only given credit for the correct product and/or reagents. Only write answers on the front of each page. Do your best to show me what you know in the time available.
To those who can dream, there is no such place as faraway.
California State Polytechnic University, Pomona 1. Provide an acceptable name for the following structure. (30 pts) O
H
SH O
Br O
O
NH2
OH O
H O O
NH2
2. Provide complete arrow-pushing mechanisms for the reactions below. Include curved arrows, lone pairs of electrons and formal charge. If resonance is important to your solution, draw the best resonance structure and one additional resonance structure to show you recognize this feature. Write the final structure and explain why it forms over any other possibility. Possible in 6 steps. (20 pts) CH3 O
O H
C H3C
Cl
H H
C O
H
Cl
+
CH3
H
N
+ CH3
2 equivalents
N H
C3H7NO
C2H3O2 CH3
California State Polytechnic University, Pomona 3.
Provide the expected product for each of the following transformations. Show regiochemistry and stereochemistry clearly, if relevant. Do NOT show mechanisms. (30 pts)
a. 1. excess NaNR2 2. Br
2 eqs. Br2,h
1. R2BH 2. H2O2,HO
b. 1. n-BuLi 2. O
O (H3CO)2P
N2
H
H3O+/H2O
(Ph)3P
c.
Br
1. NaN3 2. LiAlH4 3. workup
O
1. NaH3BCN 2. O
pH=5,(-H2O)
Cl
d. O
OH H2SO4,
OsO4
TsOH,(-H2O)
e. 1. Br2 / H2O 2. NaOH
1. LDA 2. workup 3. CrO3, py
CH3-Cu-CH3
KOH,
1. Ph-Li 2. workup
Li
f. O O
R
1. 2.
O Br
g. 1. H3B 2. Br2,CH3O
1. LiAlH4 2. workup
NaCN
h. 1. Br2, h 2. NaOH
1. O3, -78oC 2. CH3SCH3
RO (-H2O)
i. 1. H3B 2. H2O2,HO
1. SOCl2 2. HN(CH3)2
CrO3 / H2O
j. O
NH pH=5,(-H2O)
1.
Br 2. H2O
1. NaBH4 2. workup
California State Polytechnic University, Pomona 4. Propose a mechanism for the following tautomeric transformation in base and acid. (30 pts) a. (3 tautomeric changes) O
O
O N
H
H
H O
H
N H OH
O
b. (3 tautomeric changes) O
O H H
O
H N
N H OH
O
H
H OH
California State Polytechnic University, Pomona 5. Propose a synthesis for the following compound using methane, ethane, propane, cyclohexane, sodium cyanide or carbon dioxide. Your only source of radioactive 14C carbon is 14C methane, *CH4, carbon dioxide, *CO2 and sodium cyanide, Na*CN. You may also use any typical organic reagents. Often the best strategy is to work backwards from the target molecule. The last step of the synthesis should be your first step. Show the reagents and reactant for each backwards step until you reach allowable starting molecules. Also show how to do the transformations at the bottom of the page. Do not show mechanisms. (30 pts) available molecules
Br
NaCN * CH
CH4
4
*
NaCN
CO2
*
CO2
target structure O
*
N
*
*
Propose a synthetic sequence of 3 steps or fewer to accomplish the following transformations. OH
O
SiR3
OH
O
OR
O
OH
O
OH
California State Polytechnic University, Pomona 6. From the given bio-organic structure, use our simplistic mechanisms to show how each transformation could occur. If any structures are missing, fill in the necessary structures and details (look at the other side of the equation for hints). Draw in any additional atoms or structures needed to demonstrate the transformations (e.g. a hydrogen atom or a water molecule, any co-factors, etc.). Use B: if you need a base and B-H if you need an acid. Acceptable representations of possible co-factors are provided below. (40 pts) Simplified co-factors for the bio-organic game problems, if needed. H
H
H
N
O
H
H
H
R O O N
N
R
R
NAD+ equivalent
NADH equivalent
P
O
ATP
O
S
TPP ylid
N
N
N
N
N
N
H
H
H
vitamin B-6 (1o amine version)
ATP
vitamin B-6 (aldehyde version)
N
FAD
FADH2
a. H N H H OH
O
H
OH
O
R
H
O
OH
O
OH
H
H
H
H
OH N
O
O
R S
O
O
N R
R OH OH
OH
O
OH HO
HO
HO
HO
CH2
S
O
H
N
O C
H
H
O O
O
O
O
O
O
H
OH
O
S
HO
S
H N
S
N
R
N
R
R H
H OH
H
O OH
O
N
R
H OH
H
H O
N
R
O
R OH
N
H
H H
H
H
O OH
H
OH
O
H N
R
OH
R
O P
H O
OH OH
O
R N
H O
O
N
N
H
OH
R H
R
O
OH
O
N
OH
California State Polytechnic University, Pomona b. CoA
H
O
HO
S O O
P
OH
O O
OH
O
O HO
O HO
O
P
OH
O
H O
O
S
O
O
HO
CoA
ADP O O
ADP
O ATP
O
H
O
P
O H
O
O
O
O C
O
P O
O
O
O
O
H
H HO
H
R
O
O O
S H
H
O N
N
Every problem has a gift for you in its hands.
Richard Bach
CoA
N