Name:_____________________________________________________________________________________________________________
Last First MI
Chemistry233-001
Exam3
Spring2017 Dr.J.Osbourn
Instructions:The first 12 questions of this exam should be answered on the provided Scantron. You
mustuseapencilforfillingintheScantronsheet.Ensureallerasuresarecomplete.Anyquestionsleft
blankwillbemarkedincorrect.Anyquestionwithmultipleanswersselectedwillbemarkedincorrect.
Answertheremainingquestionsontheexamitself.Showallworkandprovidecompleteexplanations.
Pleasewriteyournameon:
• Thefirstpage(ExamCoverPage)
• Thesecondpage(GradingPage)
• TheScantronSheet–CircleyourLastName
PleasebubbleinyourWVUStudentIDNumberonyourScantronsheet.
ThePeriodicTable
**Pleasedonotripoffthisexamcoverpage**
Page 1 of 9
Name:__________________________________________________________________________________________________________
Last First MI
GradingPage:Exam3
Page
Points Possible
Points Earned
Multiple Choice (3-5)
24
6
18
7
23
8
20
9
15 + 2
TOTAL
100
Page 2 of 9
Multiple-Choice
Choosetheonebestanswerforeachofthefollowingquestions.Recordeachanswerontheprovided
Scantronsheet.(2pointseach)
1. Whichofthefollowingareconsideredketo/enoltautomers?
O
OH
O
and
OH
O
and
I
O
O
II
OH
O
and
O
and
III
IV
a.
b.
c.
d.
e.
Ionly
IandIV
IIonly
I,II,andIV
I,II,III,andIV
2. Theindicatedprotonsinthemoleculebeloware:
H H
Heterotopic
Homotopic
Enantiotopic
Diastereotopic
3. Rankthecompoundsbelowinorderofincreasingstability.
a.
b.
c.
d.
I
II
III
IV
I<II<IV<III
II<I<III≈IV
II<I<III<IV
II<III<IV<I
III≈IV<I<II
4. Whichoneofthefollowingstatementsisfalse?
a. Increasingsubstitutionstabilizesacarbocationbyhyperconjugation.
b. TheboroninBH3hasanemptyp-orbital.
c. Therate-determiningstepinHXadditiontoanalkeneiscarbocationformation.
d. AlkynesaremorereactivetowardHXadditionthanalkenes.
e. Noneoftheabovestatementsarefalse.
a.
b.
c.
d.
e.
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5. Howmanydifferentproductsresultfromthefollowingreaction?
Br 2
1product
2products–apairofenantiomers
2products–apairofdiastereomers
4products–twopairsofenantiomers
6. Howmanychemicallydistincttypesofhydrogenareinthemoleculebelow?
a.
b.
c.
d.
OH
2
4
5
6
8
7. Inthe1HNMRspectrumofthecompoundshownbelow,protonawillappearasa________and
protonbwillappearasa_________.
O
a.
b.
c.
d.
e.
O
H 3C
C
H2
O
C
H2
CH 3
b
a
doublet,triplet
quartet,singlet
sextet,triplet
quartet,triplet
singlet,singlet
8. WhichofthefollowingbestdescribesthefirststepofthemechanismofH-Bradditionto1-butyne?
a.
b.
c.
d.
e.
H Br
a.
H
+ Br
b.
+ Br
Br
Br
H Br
H
+ Br
c.
Br
Br
d.
H Br
H
+ Br
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9. Ranktheprotonsshownbelowinorderofincreasingchemicalshiftin1HNMR.
II
H
H
I
O
III
H
CH 3
IV a.
b.
c.
d.
e.
IV<II<I<III
IV<II<III<I
II<IV<I<III
I<IV<III<II
III<II<IV<I
10. Whichcompoundshownbelowmatchestheprovided1HNMRspectrum?
d, 6H
t, 2H
q, 2H
sep, 1H
s, 1H
5
4
3
2
PPM
1
0
OH
HO
O
HO
a
b
c
d
11. Inthe1HNMRspectrumof1-bromobutane,themostdeshieldedhydrogensarethoseboundto
a. C1
b. C2
c. C3
d. C4
12. WhichchoicebelowbestdescribesthestructureofcompoundX?
O
HgSO 4
H 2SO 4
Compound
X
H 2O
single product
a.
b.
c.
d.
e.
H2
Pd/C
pentane
2-butyne
2-pentyne
1-pentyne
2-pentene
1-butyne
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CompletionSection
Answertheremainingquestionsinthespacesprovided.
13. ProvidetheIUPACnameforeachcompoundbelowincludingE/Zwhereappropriate.(2ptseach)
a.
Br
b.
14. ProvideboththeIUPACandcommonnameforthecompoundshownbelow.(2points)
IUPAC:
Common:
15. Completetheelectronpushingmechanismforthereactionshownbelowbydrawinginthe
intermediatesintheboxesprovided,andbyaddingcurvedarrowstoshowelectronflowinevery
step.(7points)
H
H 2O
H
OH
SM
P
H 2O
or B
H 2O
H 2O
Int 1
Int 2
Int 3
16. Drawanenergydiagramforthereactionshowninquestion15.Clearlyindicatethelocationsofthe
startingmaterial,product,andallthreeintermediates.(5points)
E
Reaction Progress
Page 6 of 9
17. Predictthemajororganicproduct(s)foreachreactionshownbelow.Showstereochemistrywhere
appropriate.Ifenantiomersareformed,youonlyneedtodrawoneenantiomer.(2pointseach)
a.
H
1. BH 3-THF
2. NaOH, H 2O2
b.
H2
Pd/C
c.
H 2SO 4
OH
d.
Ph
Na(s)
Ph
Br 2
NH 3(l), -78 °C
e.
HCl
(1 equiv)
f.
Cl2
H 2O
g.
1. BH 3-THF
2. NaOH, H 2O2
h.
CH 2I 2
Zn(Cu)
18. Showthecompleteelectronpushingmechanismforthereactionbelow.Drawallrelevant
intermediatesandusecurvedarrowstoshowelectronflow.(5points)
Cl2
Cl
Cl Page 7 of 9
19. Drawarepresentative1HNMRspectrumforthecompoundshownbelow.Besuretoshowcorrect
splitting,integrationvalues,andlabeleachsignalwiththecorrespondingproton(i.e.a).(6points)
O
a
H
12
O
11
b
H2
C
C
H2
c
d
CH 3
10
9
8
7
6
ppm
5
4
3
2
1
0
20. Foreachcompoundshownbelow,determinethenumberofchemicallydistincttypesofhydrogen.
(2pointseach)
O
OH
distinct H
distinct H
distinct H
21. Synthesis:Showthesequenceofreactionsthatyouwouldneedtocarryoutinordertotransform
theindicatedstartingmaterialintothedesiredproduct.(4points)
Ph
?
HO
Ph
OH
22. Fillintheboxeswiththecompoundsthatwillundergothefollowingtransformationstogive2bromobutane.(4points)
H2
HBr
(1 equiv)
Pd/C
Single Product Formed
Br
+ en
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23. Predicttheexpected1HNMRsplitting(s,d,t,q,quin,sex,orsep)foreachhydrogeninthemolecule
shownbelow.(5points)
O
HO
H
O
Br
H
24. Drawthetautomerofeachmoleculeshownbelow.(2pointseach)
O
H
OH
25. Ineachcompoundshownbelow,circlethespecifiedprotontype.(2pointseach)
most deshielded
proton:
most shielded
proton:
most upfield
proton:
OH
O
CH 3
H 3C
Cl
Br
H
H2
C
H
C
H2
CH 3
H
H
C
H2
CH 3
26. Bonus:Thefollowingmoleculewaspreparedbychlorinationofanalkenefollowedbyan
intramolecularcyclizationreaction.Whatwasthestartingmaterialusedforthereaction?(2pts)
O
?
Cl
Cl2
O
H
Page 9 of 9