Hydration硼氢化反应.docx
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Hydration硼氢化反应
Title：
Hydrationofalkenesbyhydroboration-oxidation：
preparationofoctan-1-olfrom1-octene
、
1.Introduction/Background：
Since1937,AmericanchemistHerbertCharlesBrownhadengagedinorganicboronchemistryandcompletedthefirstpaper（carbonylcompoundsreducedbydiborane）undertheguidanceofProfessorSchlesingeroftheUniversityofChicago.Afterthat,Brownnotonlyhasmadegreatachievementsintheorybutalsoinventeddozensofreducingagents.Hydroboration-oxidationreactionisalsofoundduringtheperiod.Brownwasawardthe1979NobelPrizeinChemistry.
BriefDescriptionoftheReaction.
Reductionreactionsbetweenboraneandunsaturatedbondsbelongtoelectrophilichydridetransfermechanism.
Boranecanbemadebysodiumboronhydrideandborontrifluoride.Diboraneisdimerofborane,toxicgases,typicallydissolvedintetrahydrofurantouse.Inetherliketetrahydrofuran,therearethefollowingequilibrium:
Inthisexperiment:
BMSwasused.
Boraneiselectrophilichydridetransferreducingagent.Itfirstlyattackelectron-richcenter.Itiseasytoreducecarboxylgroupandcanreactwithadoublebond.
2.Objectives：
1）ToobtaincertainknowledgeaboutthemechanismsofHydroboration-oxidationandDirectHydration
2）Tolearnhowtoidentifysimpleartefacts
3.ExperimentalData
Reagents:
M（Octene）=25mmol,
Mw（Octene）=8x12+16x1=96+16=112g/mol
m（Octene）=25mmolx112g/mol=2.8g
BMS:
M（BMS）=（1/3x25）x1.1=8.33x1.1=9.16mmol
BMS=H3BSMe=75.9g/mol
m（BMS）=9.16mmolx75.9g/mol=0.695g
V（BMS）=m（BMS）÷density=0.695g÷0.801g/ml=0.867ml
M=（trimethylamine–N-oxidedihydrate）=111.14g/mol
m（trim）=25mmolx111.14g/mol=2.7785g
M（octene）
MW（octene）
m（Octene）
M（BMS）
m（BMS）
V（BMS）
M（trim）
m（trim）
25mmol
112g/mol
2.8g
9.16mmol
0.695g
0.867ml
111.14g/mol
2.7785g
finalproduct:
theweightofroundbottomflask=62.22g
theweightofall=64.31g
theproduct=64.31g–62.22g=2.09g
M（product）=m（product）÷Mw（product）=2.09g÷130g/mol=16.07mmol
Yield%=16.07mmol÷25mmol=64.28%
4.Mechanism
DirectHydration
Hydroboration
Results
2-octanol
1-octanol
Themechanism
Markovniko’sRule
Anti-Markovniko’sRule
whentheelectrophilicadditionreaction（suchasareactionbetweenhydrogenhalidesandalkene）,thepositivechargedgroup（suchasH+）oftheelectrophilicreagentisalwaysaddedtothecarbonthathasthemosthydrogen（leastsubstituted）andinthenegativechargedgroup（suchashalogen）isaddedtothecarbonthathastheleasthydrogen.（a）
theelectrophilicadditionreaction,thepositivechargedgroupoftheelectrophilicreagentisalwaysaddedtothecarbonthathastheleasthydrogenandinthenegativechargedgroupisaddedtothecarbonthathasthemosthydrogen.（b）
（a）Themechanismofdirecthydration:
Alkeneadditionreactionwithwaterusuallyneedacidtocatalyze.
●Generatingthecarboniumionsfirst,
●→andthencombinedwithwatertoformasalt,
●→finallyloseaprotontoformalcohols.
（b）Themechanismofhydroboration:
●Boronatomisintheabsenceofelectronsoitgetclosetothecarbonatomhasgreaterdensityofelectron.
●→Afterthat,theotherChaspositivecharge,thentheboronwantedtoreleaseHatomtoformcyclicfour-memberedtransitionstate
●→Finally,ittransformedintoRCH2CH2BH2.
Thereactionwillbeformedfor3timesuntiltheHconnectedtotheboronatomwasgone.
ThereactionshowsthatForasymmetricalkene,additionlocationfollowedbyanti-MarkovnikovRules.
（c）Oxidation:
●Firstly,borateisformed.
●Secondly,theborateishydrolysis.[Appendices1]
5.DiscussionandResults:
5.1IRanalysis
1.IRfor1-Octene
Wavenumbers（cm-1）
Typeofbond
Description
3079.60
C-Hstretch
Sharp,medium
2998.57
Sharp,strong
1642.37
C=Cstretch
Sharp.strong
994.49
C-Hbond
Sharpmedium
910.14
Sharp
2.IRforfinalproduct
Wavenumbers（cm-1）
Typeofbond
Description
3350.10
O-Hstretch
Borad,weak
2923.36
C-Hstretch
Sharpstrong
2854.80
Sharpstrong
AccordingtothestructureandIRofthe1-octanol,theO-H,C-OcanbefoundandtheO-Hwasalittleweakandboard.
AndtheC=C,C-Hbondhasgoneinthefinalproduct.
Soitcanbeconfirmedthatthe1-octanolwerepresentintheproduct.
5.2NMRanalysis
H-NMR
1-octene:
H-NMR&COSY
Thesmallpeakcanbeomittedatfirst.
Peak
Positionchemicalshift（ppm）
H2O
1.5307
Peak
Position（ppm）
Integration
Numberofhydrogen
Assignment
Peak
Descriptionofcoupling
Position
A
0.8846
3.1827
3
CH3-
D
Weak
H1
C
Weak
B
Strong
B
1.2785
6.3477
6
CH3-CH2CH2CH2
C
Strong
H2,H3,H4
C
1.3615
2.1435
2
-CH2-
D
Strong
H5
D
2,0225
2.1436
2
CH2-CH
NO
H6
E
4.9174
2.0300
2
CH=CH2
H8
4.9755
F
5.8197
1.0000
1
-CH
H7
1-Octanol
CDCl3=1H&D2O&COSY
Peak
Position（ppm）
Integration
Numberofhydrogen
+D2O
Assignment
Peak
Descriptionofcoupling
Position
A
0.8823
3.0055
3
Showed
CH3-
E
Weak
H1
C
Weak
B
Strong
B
1.3021
10.0273
10
Showed
CH2CH2CH2CH2CH2
E
Weak
H2,H3,H4,H5,H6
C
Strong
C
1.5472
2.0079
2
Showed
-CH2-
E
Strong
H7
D
1,7780
1.0602
1
Disappeared
-OH
E
Weak
H8
E
3.6271
2.0000
2
Showed
CH2-OH
H9
4.7573
0.2893
Showed
HOD
TheH-NMRthataddedD2OindicatethePositionof–OH.BecauseOHisactiveandthechemicalshiftisnotstable.D2Ocanreactwith–OHandproductHODwhichreplacethe–OH.
AfterHydration；
1）allthehydrogenatomsmovetodownfieldexpectCH3.
2）–CHdisappeared
3）OHappeared
1-Octene
C-NMR&DEPT
Peak
Position（ppm）
Depth135
Depth90
Assignment
Position
G
14.0866
Positive
Disappeared
CH3
C1
H
22.6459
Negative
Disappeared
CH2
C2orC3orC4orC5orC6
I
28.8509
Negative
Disappeared
CH2
J
28.9381
Negative
Disappeared
CH2
K
31.7590
Negative
Disappeared
CH2
L
33.8506
Negative
Disappeared
CH2
M
114.0729
Negative
Disappeared
CH2
C8
N
139.2525
Positive
Showed
CH
C7
InDepth90°,onlyCHbondwillbeshowed.
InDepth135°，CH2bondwillbedownwardpeakandCH3CHbondwillbeupwardpeak.
HSQC
CPeak
Hpeak
Descriptionofcoupling
Assignment
Position
G
A
Strong
CH3
C1
H
B
Strong
CH2
C3
B
Medium
I
B
Strong
CH2
C4orC5
C
Strong
CH2
J
B
Strong
CH2
C4orC5
C
Strong
CH2
K
B
Strong
CH2
C2
B
Weak
L
D
Strong
CH2
C6
HSQCtellsabouttherelationshipbetweenHandC.AlltheinformationwerematchedtheaboveCNMR,HNMR.
IJpeakswereverycloseandtheybothhavestrongcouplingwithBCpeakswhichrepresentH2,H3,H4,H5.ItishardtoidentifywhichcarbonatomtheIJpeakrepresents.
1-Octanol
C-NMR&DEPT
Peak
Position（ppm）
Depth135
Depth90
Assignment
Position
F
14.0779
Positive
Disappeared
CH3
C1
G
22.6357
Negative
Disappeared
CH2
C2orC3orC4orC5orC6orC7
H
25.7549
Negative
Disappeared
CH2
I
29.2840
Negative
Disappeared
CH2
J
29.4069
Negative
Disappeared
CH2
K
31.8201
Negative
Disappeared
CH2
L
32.7814
Negative
Disappeared
CH2
M
62.9905
Negative
Disappeared
CH2
C8
HSQC
Cpeak
Hpeak
Descriptionofcoupling
Assignment
Position
G
B
strong
CH2
C2orC3orC4orC5orC6
H
B
strong
CH2
I
B
Strong
CH2
J
B
Strong
CH2
K
B
Strong
CH2
L
C
Strong
CH2
C7
G,H,I,J,K,allhadstrongcouplingwithBpeakwhichmadetherecognitiondifficult.
AfterHydration
1）CHdisappeared
2）C7wenttohighfield.
TheDiglyme
H-NMR
Peak
Position（ppm）
Integration
NumberofH
Assignment
Postion
A
3.3826
6.0000
6
CH3-,CH3-
H1,H6
B
3.5556
3.9790
4
CH2-.CH2-
H2,H5OR
H3,H4
3.5647
3.5745
C
3.6426
4.0474
4
CH2-.CH2-
3.6615
C-NMR
Peak
Position
Depth135
Depth90
Assignment
D
58.9131
Positive
Disappeared
CH3
E
70.4740
Negative
Disappeared
CH2
F
71.8485
Negative
Disappeared
CH2
Thestructureofdiglymeissymmetry.Sothespectrumonlyshowed3peakswhichpresent2bondperpeak.
Thedifferencebetween1-octanoland2-octanolonH-NMR.C-NMR,IR
1-Octanol
2-Octanol
Structure
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2OH
CH3-CH2-CH2-CH2-CH2-CH2-CHOH-CH3
IR
Nodifferences,thesamebond
Nodifferences,thesamebond
H-NMR
Thereare6CH2bondinsimilarchemicalenvironment
NOCHandOHpeak
There5CH2bondinsimilarchemicalenvironment.
1CHand1OHpeak
C-NMR
Depth135°：
6negativepeaks,1positivepeaks
Depth135°：
5negativepeaks,2positivepeaks
Depth90°:
nopeak
Depth90°：
1CHpeak
Thecrudeproduct、
H-NMR
Peak
Position（ppm）
Integration
NumberofH
Assignment
Position
A
0.8827
3.1180
3
CH3
H1
B
1.2303
12.7927
12
CH2CH2CH2CH2CH2CH2
H2,H3.H4.H5.H6,H7
C
1.3313
1.6152
D
1.5394
0.9521
1
H-OH
water
E
3.3863
1.0015
1
-OH
H8
F
3.6412
2.0000
2
CH2-OH
H9
Comparedwiththepureproduct.,itcanbeidentifiedthatNoCHbondwereformedandonlyoneCH3bondwereformed.
→Only1-octanolwereformed.
C-NMR&COSY
Peak
Position（ppm）
Depth135°
Depth90°
Assignment
G
14.1059
Positive
Disappeared
CH3
H
22.6663
Positive
Disappeared
CH2
I
25.7502
Negative
Disappeared
CH2
J
29.3242
Negative
Disappeared
CH2
K
29.4036
Negative
Disappeared
CH2
L
31.8238
Negative
Disappeared
CH2
M
32.8194
Negative
Disappeared
CH2
N
58.4861
Positive
Disappeared
DiglymeCH3
O
63.1144
Negative
Disappeared
CH2
P
70.5628
Negative
Disappeared
DiglymeCH2
Q
71.9358
Negative
Disappeared
DiglymeCH2
TheC-structuredidn’tchange.
→Sonoex
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