Download 06 MC /08 MC /08 NMR

Chemistry 211
Exam 4
Fall 2015
Linda Waldman
)
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J)
4)
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6)
1
2
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Page
1
Cover page
Page 2
114 tvlo
Page 3
/06
Page 4
116 MC
Page 5
t10 Mc
Page 6
/08
Page 7
118 Short answer
Page 8
126 Products/ Mechanism
Page 9
/08
Total
1100 (actually 106)
MC
MC
NMR
LSW F15
I.
ln it ia ls
11E'l
Multiple Choice. (2 points each): Write the best answer in the box provided.
l. Which of the following alkenes is expected to have the highest heat of hydrogenation? (Least
stable isomer)
A) l-pentene B) trans-2-pentene C) cis-2-pentene D) 2-methyl-2-butene
ofthe following is not a possible reaction ofa carbocation?
addition of a nucleophile
rearrangement to a more stable carbocation
tt'
C) addition of a proton to form an alkane
D) loss of a p-hydrogen to form an alkene
A
2. Which
./1
A)
B)
+
- C)'
t
x^
--+
ofHCl to 3-methyl-l-pentene gives two products. One ofthese is 2-chloro-3methylpentane. What is the other product? (Think rearrangement).
l
3-chloro-2-methylpentane
2-chloro-2-methylpentane
3. Addition
A)
B)
-chloro-3-methylpentane
3-chloro-3-methylpentane
4.Predictwhichofthefollowingalkenesreactsthefastestwith
A)
B)
o
C)
D)
CH:CHzCHzCHzCH=CHz
C)
cIs-CH:CHzCH=CHCHzCH: D)
HClLtA"t]':Y:kJ'"b-\
trans-CHtCHzCH:CHCHzCH:
(CH:)zC=CHCHzCH:
D
5. Which of the following alkenes gives 1-bromo-2-methyl-2-pentanol upon reaction with
Br2/II2O?
gr
dt
niY
I
A) CHICH:CHCH(CHrh B) CH3CH2CHCH:CHz
D
I
I
q.
C)
CH-r
oll
=C1ar.,x
CHTCHT Cu
/
g
D) cH3cHzcH2 C:CH
I
CH:
I
6. Which of the following is least likely to react with an alkene?
A)
H3O+
B) BrCt
C) CII3CII2 (cthyl radical)
D) Na(X)H2CH3
7. Which of the following gives acetone, (CH:)2C=O, as one of the products of its ozonolysis?
A)
B)
c)
D
D)
A
fr'rPn'
2
LSW
F15
8. Which ofthe following series ofreactions would convert cyclohexanol to
epoxycyclohexane?
lnitials
1,2-
H€Y
c
olt
2
o
A) (l) #,*rr,.r,
(2) Br2,l'l2O
B) (l) 84, rsht
(2) NaOCI{2CI{3
C)
(l)
o
1r'
/
(2) CH3COOH, CH3CO2H
H2soi,heat
V
D) (l)H2Soa,heat
(21
Q) ZI,H2O
h
9. A compound is treated with ozone followed by zinc in water to give the following three
products. Which structure below best fits the data?
o
o
lt
c
il
nrc'i-cn,
Htc-
2y
7
2
A
A)
/
I
o $
II
o
a
c0
0
H
,c(crrrb
Ag c9
r'
t\cti 3 h ac
I
B) (CH3bHHCH2CH2CH{HCH3
c) H2c{cH2cH1f1n"r'
o
t,
?
l-Lilt
tt
C!-t
cHr F
l)) HzC{IICIIzCH2C{(CH3h
-..-t
10. Which of the
\
following does not give 1-bromo- 1-methylcyclopentane
as the
major product?
CH
HBr
It()()R
CHr
c)
6r
Ar
B)
light
Ht)
HBr
---------------->
D)
A
Br,
CHt /
6r
IIBr
3
(_.)
LSW F15
I
l. Which species below
ln itia ls
KEY
acts as the nucleophile in the acid-catalyzed addition of water to an
alkene? .x
x - .q: -I) -A) H:O' B) rhecarbocation QL $\ D) Hzd
D
12. The rearrangement which occurs in the
+
(CH3)2CHC^H{H2
}vz
I
HBr
------------>
I
following reaction can be described as a
A) hydride shift from C-2 to C-l
C
on shift from C-2 to CB) h dride shift from C-3 to C-2
methyl group shift from C-3 to C-2
a
3. Identify the nucleophile in the following electrophilic addition reaction.
d,r
,
JI
(CH3)2C:CH2 +
[N3
?,,
-------------)
a
A) N?
B)N o
CH3CCH2I
I
Ni
C) ICI
cr
D)
Io
following is the rate-determining step in the acid-catalyzed addition of water to
14. Which of the
2-methylpropene?
+H l
-{)
l(lH-r).C=CH,
B)
(('H-r),r(l@ + H,(_)
------------>
@
(l) (cH3)lc-()H,
+ H'o
I))
(CHl)-l(l@
+ H,()
i(_lH-r)3c@
+
H.,O
A
@''
((lH-r.)3c-()H.
........- (.C-HJ3C-()H
-..............
+H
(rlH3).'(l=cH.'
-l
ofthe following gives only one organic product on acid-catalyzed hydrolysis?
A) 2-hexyne B) 3-hexyne C) 2-heptyne D) 3-heptyne
15. Which
-B
SYnnehlc
16. Identify the electrophilic species in the
f,,
lIzC-C,
H2O, H3O+
.---------------
following reaction.
(cII3)3COII
CIIr
c
A) HzC:C(CHI)
B H o
c) H: ot
(CH3)3COH
following are conjugated dienes?
1.2-octadiene
II. 1.3-octadiene III. 2,s-gctadiene
,I.
A) only B) only II I C) I and
D) II hnd
17. Which of the
I
I
Y.,.r"^
ebn',
18. Which of the
A)
B)
II
rll
lV.
lso
B T
I,7-octadiene
.1
l5o
following compounds most readily undergoes solvolysis with methanol?,
(E)-l-bromo-l-butene Vif
C) 3-bromo-l-butenr2-bromo-
I
-butene "
1' ,,.a1
..,7--.2'
D)
4-bromo- l -buten
to
e
L
...-{"t
' Y
ar
4
t^iti"t
LsW F15
19. What major product would you expect from this reaction?
I
CH:
Hzo
I
--7
,|
C
+lzo
CH:
A)
B)
-dimethyl-2-butanol
3,3-dimethyl- l -butanol
3,
r)
t
cat. H2SO4
CH:
H
L
+
H
H-c//c
KEy'
3
D)
I
3-dimeth v 1-2-butanol
2,2-dimethyl-3-butanol
20. Ozonolysis of an alkyne gave the two compounds shown below. What is th
the original alkyne?
CHTCHzCHzCOzH and (9Hr)rQ
of
Ltlrcl/
A)
B)
2.2-dimethyl-3-fftyne
3,3-dimethyl-4-fftyne
,a7
C-.
,2-dimethyl-llnl v -3-
/
21. Which reaction sequence below would work best in converting 3-pentanol into 2,3dibromopentane?
A) (1)
HzSO+, heat
B) (1)
H2SOa,
U) (1) Br2,
v
(2)
IIBrY
heat/ (2) Hztptx
lightX
I D) (1) HzSOr, heat
(3)
Br'2,
(3)
2 Br2, tight
light
(2) H2SOa, heat (3) H2lPt X
(2) tsr2
22. Which sequence of reactions works best in_qlnthesizing ci^s-3-nonene?
A)
(1)l-bufyne,NaNH2
(2) l-bromopentane
(3) Na, NHj 4zr5
C) (1) l-pent"vne,
NaNH2
(2) l-bromobutane
(3) H2O, H2SOa/HgSOa x
B) (1)l-butynelNaNH2 C
(2) l-bromopentane
(3) H2, Lindlar Ptl f,tr
CeLl:g
'
€
----
D) (1) l-pentvne, NaNH2
(2) l-bromobutane
(3) 2 HCt
(4) NaNH2,[21af
23. What reagents would be required to accomplish the conversion shown below?
Br
Br
make
CH:
CH:
A)
B)
b
into
c) r'Nuocgr,tt.r,g#
and light.
peroxr
S
s
5s
KOtBu. then Brz and lieht.
6ap"e.rtc'
5
LSW F15
ln it ia ls
KE
24. Which one of the following compounds fits the C-I3 NMR spectrum shown below?
3(Yt
la,
l@
l()
txt
l(D
Hrl
zB)
Nb
q
6
to
d,
&
x
06
i
H2
-7
D
TMS
3 qv
.)
?
3
D)
q
4
of I -butene wi bromine, Br2, in aq us solution gives primarily 1-bromo-2butanol. Identify the nucleophilic species in the reaction
tlzO
25. The reacti n
A) Brz B) Br
C) HzO D) HOBr
i) =
e\
cAz
26. The product(s) in the following reaction is (are):
cHz
tt2lPd
C.
L
a*3
{
C\5
c
llrc
A)
B)
C)
D)
only trans-l-4-dimethylcyclohexane.
onlycrs-1-4-dimethylcyclohexane.
both trans and cis-l -4-dimethylcyclohexane.
It's impossible to tell.
--'i
C)
27. What product results from this reaction?
(a
h
Clz
-.cH
V
OH
...toH
CH:
A
ts
\
CI
3
,
oil
Hzo
-+?
OH
A
B
e
cl
OH
CH:
C
P,'
cHr
D
6
LSW F15
lnitia
ls
II. Short Answers: (3 pts each) Mark the correct answer in the box provided.
I
.
e
A compound, C sHzq, is reacted with excess hydrogen using a metal catalyst. One equivalent
ofthe compound consumed]!ryff cuivalents.of-lrydroele.u.--How many rings did the original
r
compound have?
fHD"
2.
A
4
t/z
-fr2 t4
\>3 H2
f ltD,l
a
u5ed -- 4-z
t'
982
3 //
a
Propyne is treated with sodium amide in ammonia then methylbromide is added. The
reaction proceeds quickly and the product, K, is treated with a poisoned (Lindlars) catalyst
on palladium. After purification the major product compound L is isolated. L is then treated
then treated with bromine in the dark to produce M. Identify compound M
using its IUPAC name to indic a* the stereochemis try.
\riflElt.
/
4
-1
-/.- -CU
3.
2>
+z-.\a ,Ufri*
j
A
B)
6rR
t
C H3
CH 3
) cHr
cHr
CH:
?o
'N"
,2
-)
2 r)
tr
fr,ff
III
decre^t3$nytth (stropr]lFfirst).
II. CHrCH: III. NH2 IV. HC:C:
Stroya$
Arrange the foflowing in orderof
L
CH3CH2O
l)€iYl91
5.
1,,3),6.*ob.tb*c
Rank the following in order of decreasing reactivity with bromine, Brz.
30
4.
2 5'
fr 4
Compound X, CrHr:Cl, is reacted with sodium ethoxide and gives a single elimination
product Y, CrHrz. Treatment with ozone followed by zinc and water gi ves the compound
below. Identiff both X and
O
Y.
x)Y)
X
o
I
Z
,
5
II
3
Y
+e
lllte:''I)
7
L?
l-
LSW F15
III.
ln itia ls
KfY
Predict the Products: (4 pts each) Write the major product for each of the following
write in the stereochemical designation rather than draw it, if you prefer. If a racemic
mixture is predicted please write "racemic".
H2O, H2SO1
CII3CH2C=CH
dfi
u3 chTc,+3
I ..(
ni4 bt
el
,rc--t
cl
HBr
--------------t,
tl 6r
(.)
(lH.l
H-r('
i'
ll
(lH
(l
Hj(l
acld
cH.r
lr
)
,r
,$1
cb lllt(
clz
ub
n*)
--------------)
cHr
a
ttt
il l)BH3/TSF'
,,,,,,;|ru
tut
.---------------
,
tlg
tI
E
o tl
IV. Mechanism (6 pts): Draw the complete correct mechanism for the following
reaction including all electrons and the correct arrow type.
l. Bromination of
e
by Bf2
1no
p",o,.16"g.
+
oO
+:B
oo
?ta
B.i
+rbf
6
)
.r;l
I
s6;Y
8
0
Bri
Cll
z
lnitia ls
LSW F15
KEY
provides the lH NMR spectrum shown below, identifu
the compound. (The numbers above the peaks are integration values.)
V. Spectroscopy: (8 pts) A CsHr compound
1.00
3.00
CsHs
1.99
1.98
4.5
tltrt
I
43.532.52
1.5
0.5
1
The information from the lH NMR tells me:
Peak
Chemical
shift
Split
lntegration
Equivalent
Group
Hydrogens
(E)
2.L5
Group with neighbor
Neighbor
Hyd rogens
PPM
A
Number of
t
2
B
1.86
s
1,
c
7.47
M(6)
2
D
0.98
t
3
L
-.-)
ct@'t
a
oL
/-L-lnl
1
L
ZZ
\
C#, Cilz Clls
2
cilt
The structure of the product with appropriate labels (A, B, C, D) is:
crta
cb ch+"
DE
h
9
l-t