1.
a.
Rank the following compounds in the trend requested. (15 points each)
Rank by acidity. The most acidic compound is 1, while the least acidic compound is 5.
OH
SH
2
3
1
Cl3C
NH2
5
4
b.
Rank by reactivity with HBr. The compound that reacts the fastest with HBr is 1, while
the compound that reacts the slowest with HBr is 5.
3
2
5
1
4
c.
Rank by boiling point. The compound with the highest boiling point is 1, while the
compound with the lowest boiling point is 5.
O
4
HO
OH
1
OH
OH
5
2
3
2.
Fill in the missing products for the following reactions. Assume proper work-up for each
step. Write structure in the boxes provided. (5 points each)
a.
O
OsO4, H2O2
O
OH
OCH3
OCH3
OH
b.
CH3
H 3C
OK
CH3
Br
O
Cl
O
O
MgBr
OH
O
c.
O
O
H3CO
NaBH4
OH
CH3MgBr
(excess)
H3CO
OH
H
O
OH
H
3.
Consider the following hydrocarbons.
a.(10) The final steps of the synthesis of trimethylphenalene are shown below. Fill in the empty
boxes below.
CH3
CH3
HO
O
CH3
H2SO4
LiAlH4
H 3C
H 3C
CH3
CH3
H3C
CH3
trimethylphenalene
b.(6)
How many degrees of unsaturation are in trimethylphenalene?
9 – one for each π bond and one for each ring
c.(15) For each pair of alkenes shown below, circle the compound that will be the most
exothermic when reacted with hydrogen gas and a catalyst. The fully hydrogenated alkane is
lower in energy than the alkenes shown. In each pair, therefore, which alkene will generate more
heat upon hydrogenation?
CH3
CH3
versus
H3C
CH3
versus
CH3
CH3
versus
H3C
CH3
H 3C
In all cases, the less stable alkene will be more exothermic hydrogenation.
4.
Draw the preferred product obtained for the following reactions. Assume proper work-up
for each step. (7 points each)
a.
Br2, H2O
OH
Br
b.
KMnO4
H+, !
O
O
OH
c.
O
OH
O
NaBH4
O
O
O
d.
O
O
OH
LiAlH4
O
HO
OH
e.
O
OH
CH3CH2MgBr
f.
OH
1) NaNH2
2)
O
g.
1) NaNH2
2) CH3Br
3) Na, NH3(l)
h.
HBr
(excess)
Br Br
i.
1) (Sia)2BH
2) H2O2, NaOH
H
O
j.
1) PhCO3H
2) H+, CH3OH
OCH3
OH
k.
OH
1) H2SO4
2) BH3•THF
3) H2O2, NaOH
OH
l.
Br
HBr
5.
Indicate a route to synthesize the following compounds using the starting materials
shown. You may use any other inorganic or organic reagents you desire, but you must use the
starting material shown to synthesize the product. More than one step may be required. Must
indicate what reagents are being used, and the proper sequence of steps required. (15 points
each)
a.
?
O
OH
1) O3
2) CH3SCH3
H2SO4
H+, H2O
O
b.
?
OH
HgSO4
H2SO4
O
CH3MgBr
OH
6.
When compound A (molecular formula C6H8) was partially hydrogenated with hydrogen
gas and palladium catalyst, four products were isolated (compounds B-E). Partial hydrogenation
means that not enough hydrogen was used to hydrogenate every π bond to completion. (When
the reaction was performed with excess hydrogen gas, only compound B was obtained.) When
the products were separated, they were reacted with ozone followed by dimethylsulfide.
Compound B did not react under these conditions. Compound C yielded acetic acid and
butanoic acid. Compound D yielded acetaldehyde and glyoxal (CHOCHO as shown below).
Compound E yielded acetaldehyde and butanal. Draw the structures for compounds A-E in the
space provided. (20 points)
Compound A
1) O3
2) CH3SCH3
H2
Pd
no reaction
Compound B
Compound C
Compound D
1) O3
2) CH3SCH3
O
1) O3
2) CH3SCH3
O
O
b.(5)
__________
Compound D
H
__________
Compound E
Which compound (B-E) would react the fastest with HBr? (circle the correct answer)
B
c.(5)
O
O
H
__________
Compound C
H
H
H
Compound E
__________
Compound B
OH
OH
1) O3
2) CH3SCH3
__________
Compound A
O
O
C
D
E
Which compound (B-E) would react the slowest with HBr?
B
C
D
E