Chapter 11 Alcohols, Ethers and Phenols Alcohols—structure, nomenclature and properties as before Phenol—benzene with OH attached Ether—ROR, where R = alkyl group Simple ethers are named using the alkyl group attachements. Butyl pentyl ether above. ethyl methyl ether tert-butyl ethyl ether diethyl ether In more complex molecules, ethers are named as alkyloxy. Examples methoxy, ethoxy… 6-tert-butoxy-5-ethoxy-2-methoxy-4-methyl-3-octen-1-ol OH O O O O O O OH O 1
Transcript
Chapter 11 Alcohols, Ethers and Phenols Alcohols—structure, nomenclature and properties as before Phenol—benzene with OH attached
Ether—ROR, where R = alkyl group
Simple ethers are named using the alkyl group attachements. Butyl pentyl ether above. ethyl methyl ether
tert-butyl ethyl ether
diethyl ether
In more complex molecules, ethers are named as alkyloxy. Examples methoxy, ethoxy…
No hydrogen bonding possible so ethers have low boiling points similar to hydrocarbons However because of Oxygen ethers are good solvents can dissolve organics and ionics.
Some common examples- Methanol—wood alcohol, originally prepared by distillation of wood
toxic, small quantities can cause blindness, large quantities—death Ethanol—drinking alcohol, made through fermentation of sugars sugars can come from many sources mostly grain, hence, grain alcohol
Fermentation can only generate maximum 12-15%v/v of ethanol due to high solubility of water. To get higher percentages water must be distilled away. Hence Jack Daniels Distillaries…Proof = 2 x’s the %. 100 proof = 50%. Even with distillation highest percentage possible is 95%. The last 5% of
water can not be eliminated because it forms an azeotrope that boils at lower temperature than the ethanol itself. This is pure grain alcohol—190 proof = 95%. To remove the last 5% water impurity, benzene is added and a new azeotrope forms that boils even lower than the water/ethanol azeotrope. 200 proof = 100 % is called absolute alcohol. It is denatured by adding a toxic
substance such as methanol or benzene. This is called denatured alcohol. Ethylene glycol—antifreeze Diethyl ether—flammable used as anesthetic
O O
O O
O
2
Synthesis of alcohols from alkenes 1) Acid-catalyzed hydration of alkenes—Chapter 8, not useful synthetically.
Rearrangements make this a very non useful reaction. Markovnikov addition.
2) Oxymercuration-Demercuration—Markovnikov addition. Usually less than one
hour in 90-100% yields.
The mechanism for the removal of the HgOAc is not understood.
Reaction of Alcohols The OH of the alcohol is basic and can act as a nucleophile. It is a very bad leaving
group. Protonation of the alcohol makes the OH a good leaving group. Water has a pKa of 15.7. Most alcohols have higher pKa than water(the exception being methanol). This is due to the steric hindrance created by the alkyl groups. The large the alkyl group = higher the pKa which = less acidic.
Acidity
Water > ROH > Alkyne > H2
> NH3 > RH
Basicity R- > NH2
- > H- > Alkynide- > RO- > OH- CONVERTING OH TO GOOD LEAVING GROUP Mesylates, Tosylates and Triflates make very good leaving groups. Ms-Cl, Ts-Cl,
Tf-Cl in the presence of base converts alcohols to those very good leaving groups. These mesylates, tosylates and triflates can undergo SN2 reactions very easily. In the process of converting OH to these good leaving groups the stereochemistry of the carbon remains unchanged(retention of configuration). However once the SN2 reaction occurs, then inversion of configuration occurs. Triflates are such good leaving groups that even vinylic cations can form.
OH
Base(NaH...)/MsCl
Base(NaH...)/TsCl
Base(NaH...)/TfCl
OMs
OTs
OTf
Ms = R = CH3
Ts =
Tf = R = CF3
S
O
O
Cl R
CH3
5
CONVERTING ALCOHOLS TO ALKYL HALIDES Acids such as HCl and HBr can be used to convert alcohols to alkyl halides.
These reactions lead to carbocations and rearrangements(Primary and methyl still use SN2 mechanism to form the alkyl halides). HCl and HBr will usually produce alkylhalides instead of elimination(dehydration) products because Cl and Br are good nucleophiles. Recall if you want dehydration you add sulfuric acid or phosphoric acid. HCl and HBr work fine for allylic, benzylic and tertiary alcohols. However primary and secondary are too unreactive to work with HCl. So lewis acids are usually added to increase the reactivity. Phosphorous tribromide and thionyl chloride are modern alternatives that work extremely well. With primary and secondary alcohols phosphorous tribromide and thionyl chloride proceed with no carbocations and no rearrangements.
To prepare Ms, Ts or Tf add PCl5 to the corresponding alcohol.
S
O
O
HO R
PCl5
S
O
O
Cl R
Ms = R = CH3
Ts =
Tf = R = CF3
CH3
OH
S
O
O
Cl ROL
L = Ms, Ts or Tf
HB OL
6
OH3
Br
PBr3
O
PBr2
Br-
H HOPBr2
This can react twice more with alcohol to brominate the alcohol
3
OH ClS
O
ClCl
OS
OClH
Cl-
OS
Cl-
OCl
N trialkyl amines(such as triethylamine(TEA))are used to scavenge the HCl that is formed in this reaction.
7
Synthesis of Ethers BY DEHYDRATION OF ALCOHOLS Primary alcohols in the presence of acids create ethers with the elimination of
water. Secondary and tertiary do not work well. Alkenes form instead(dehydration). Also mixed ethers do not form using this method.
OH
2H2SO4
O
OH
H2SO4
2o and 3oalcohols are easily dehydrated
H2SO4
Reactions works ok with 1o since they are hard to dehydrate.
OH
OH
+OH
H2SO4
O
Does not form.
8
WILLIAMSON SYNTHESIS The alcohol is deprotonated with a base such as sodium hydride. Then it reacts in
an SN2 fasion with an alkyl halide. This results in the formation of an ether. Problem 11.20—retention vs. inversion. One reaction only occurs at the oxygen. Therefore, retention of configuration of the original carbon is observed. The other reaction involves an SN2 attack and inversion of configuration.
OH O
OH
OH
O
O
1) NaOCH3 2) CH3I
1) NaOEt 2) CH3CH2OTs
1) OK 2) OMs
The alcohol can be 1o, 2o, or 3o. The
base should be an alkoxide base such as
sodium ethoxide. The leaving group can be
halogen or sulfonate. This is SN2 reaction.
Therefore, 1oor 2o carbon attached to leaving
group only.
9
PROTECTING GROUPS Ethers can be used to protect alcohols. The alcohol is converted into an ether that
is unreactive. Then reactions can be carried out on the compound without affecting the alcohol. Later the ether is removed to reveal the unchanged alcohol. The protecting group should be fairly nonreactive and should be easily removable. Tert-butyl ether is an OK protecting group. It is removed by dilute acid. One of the more modern preferred protecting groups is tert-butyldimethylsily ether(TBDMS) which is a large bulky group that is nonreactive to most reagents. It is easily removed in the presence of fluoride ion(TBAF—tetrabutylammonium fluoride).
OH OTBDMS
TBDMS-Cl
imidazole/DMF(pyridine can also be used)
Si
Cl
Bulky group. Can withstand pH from 4-12.
OTBDMSTBAF/THF
T BDMS-Cl =
OR OP
P = protecting group
OH
TBAF =
N
F -
OR (Bu)4NF
Silicon-fluorine is one of the strongest covalent bonds.Fluorine seeks out the sil icon and bonds to it.
10
REACTIONS OF ETHERS Ethers in general have low reactivity and usually act as solvents which can
dissolve both covalents and ionics. The oxygen of the ether is basic and nucleophilic so some reactions are possible. Ethers react with strong acids to form alkyl halides.
EPOXIDES Epoxides are a special class of ethers. Epoxides are three-membered cyclic
ethers. Alkenes will in the presence of peroxy acids(such as MMPP) will convert into epoxide. In the formation of the epoxide the stereochemistry of the double bond is retained(like in the Diels-Alder reaction). Epoxides are extremely reactive. Dilute acids can open up the epoxide to form a diol. Epoxides can also undergo nucleophilic attack. Just like in the halohydrin reaction from chapter 8, the nucleophile attacks the more substituted carbon of the epoxide if the reaction is acid-catalyzed(formation of carbocation-like intermediate). If the reaction is base-catalyzed the nucleophile attacks the least substituted carbon(SN2 reaction). The attack of the nucleophile on the epoxide leads to an anti-product. If you use an alkoxide base(methoxide) the reaction produces a reactive intermediate. This reaction keeps repeating creating a polymer chain. This is called anionic polymerization. Methanol can be added to quench(stop) the reaction.
O HBrBr
Br
AND
11
O O+M M P P
O
OOH
O
OM M P P =
OH+
OH
HO
This is similar to the addition of acids to non-cyclic ethers. This is an anti-hydroxylation of an alkene. Unlike KMnO4 and OsdiO4 which give syn dihydroxylations. This reaction is analagous to the bromination reactions of Ch. 8.
OH
HO
+
Bases(nucleophiles) can also be used to open cyclic ethers(they can not open non-cyclic ethers). The base-catalyzed reaction is a SN2 reaction. This also leads to anti-addition.The incoming nucleophile attacks at the least substituted carbon.
Acid-catalyzed reactions can be carried out with other nucleophile. This will alsolead to anti-addition. The incoming nucleophile adds to the more substituted carbon,as in the halohydrin reaction. The intermediate is unsymmetric and resembles a carbocation.
OHCl
Cl
HO
ONaCl
OH
ClStronger nucleophiles are needed. I usedCl just to make the point.
12
CROWN ETHERS Polar aprotic solvents greatly enhance and speed up SN2 reactions. However, there
are disadvantages to polar aprotic solvents. They usually have high boiling points making them tough to remove at the end of the reaction. They need to be purified to be used in reactions(distilled). This is costly and time-consuming. Also at high temperatures, polar aprotic solvents can decompose. Nonpolar aprotics would be excellent solvents. Nonpolar aprotics would still greatly enhance SN2 reactions but without all the problems of polar aprotics. Benzene, toluene, hexanes, dichloromethane are examples of nonpolar aprotics. They are all low boiling point and fairly easily purified. The problem is the nonpolar aprotics do not dissolve ionic reagents because of their nonpolar nature. SN2 reactions usually require ionic reagents(sodium iodide, potassium bromide…). A recent development called phase-transfer catalysts(PTC) help solve this problem. PTC are both hydrophilic and lipophilic. They can go into the aqueous layer grab the anion and then bring it into the organic layer where the reaction will take place. They will then bring the leaving group back to the aqueous layer and pick up another anion to start the process over again. Tetrabutylammonium fluoride is an example of a PTC. SN2 reactions work extremely well with PTC. Other reactions are possible. Oxidation with potassium permanganate can be carried out with PTC. A test for alkenes is to take a potassium permanganate solution with TBAF. An unknown is added to the permanganate(purple) solution. If the unknown contains double or triple bond then the purple solution will turn brown.
13
Crown ethers are also good PTC. Crown ethers can completely solvate the cation of the ionic substance creating a naked anion which then undergoes an SN2 reaction. The crown ether acts as the host and the cation that is trapped is called the guest. Crown ethers are named x-crown-y. X stands for the total number of atoms. Y is the number of oxygens. 18-crown-6 is especially good at solvating potassium.
O O
O
O
O
O
OO
O
O
O
O
36-crown-12
14
REACTIONS FROM CHAPTERS 8, 11 and 12
HCl
Br2
H3O+
HBr/H2O2
1) HgAcetate, THF, H2O
2) NaBH4, NaOH
HBr/CCl4
1) BH3:THF
2) H2O2, OH-
1) Hg(O2CCF3), CH3CH2CH2OH
2) NaBH4, NaOH
Br2/H2O
Cl
Br
Br
OH
Br
Br
Br
OH
OHOH
OCH2CH2CH3
15
Diazomethane
MMPP
1) MMPP
2) HBr
1) MMPP
2) NaBr
OH
OH
OH
CH2I2/Zn(Cu)/diethyl ether
1) MMPP
2) H+
KMnO4, OH-, H2O, cold
1) OsO4, pyridine
2) NaHSO3, H2O
Br2, H2O
O
OH
OH
OH
OH
Br
Br
OH
OH
Br
16
6
5
4
3
2
1
a
b
c
8
7
6
5
4
3
2
1
a
7
6
5
4
3
2
a
b
1
7
6
5
4
3
2
b
c
1
a
1) KMnO4, OH-, H2O
heat
2) H3O+
1) KMnO4, OH-, H2O
heat
2) H3O+
1) KMnO4, OH-, H2O
heat
2) H3O+
1) KMnO4, OH-, H2O
heat
2) H3O+
6
5
4
3
2
1
O
OH
6
5
4
3
2
1
O
OH
7
6
5
4
3
2
O
1
7
6
5
4
3
2
O
1
+c
b
a
O
OH
+
+
+
CO Oa
b
a
O
OH
c
b
O
a
17
6
5
4
3
2
1
a
b
c
8
7
6
5
4
3
2
1
a
7
6
5
4
3
2
a
b
1
7
6
5
4
3
2
b
c
1
a
1) O3, CH2Cl2, -78oC
2) Zn, AcOH 6
5
4
3
2
1
O
H
6
5
4
3
2
1
O
H
7
6
5
4
3
2
O
1
7
6
5
4
3
2
O
1
+c
b
a
O
H
+
+
+
b
a
O
H
c
b
O
a
1) O3, CH2Cl2, -78oC
2) Zn, AcOH
1) O3, CH2Cl2, -78oC
2) Zn, AcOH
1) O3, CH2Cl2, -78oC
2) Zn, AcOH
O
a
HH
18
6
5
4
3
2
1
a
5
4
3
2
1
a
b
3
2
1
a
b
c
d
1 mole HBr
2 moles HBr
1 mole Br2
2 moles Br2
HgSO4, H2SO4, H2O
1) O3
2) Zn, AcOH
or
1) KMnO4, OH-
2) H+
1) O3
2) Zn, AcOH
or
1) KMnO4, OH-
2) H+
1) O3
2) Zn, AcOH
or
1) KMnO4, OH-
2) H+
Br
Br
O
Br Br
BrBr Br
6
5
4
3
2
1
OH
O
H
a
OH
O
5
4
3
2
1
OH
O
b
a
OH
O
3
2
1
OH
O
d
c
b
a
OH
O
+
+
+
BrBr
19
OH
OH
OH
NaH, TsCl
NaH, TfCl
NaH, MsCl
OH
TBDMS-Cl, pyridine
1) TBDMS-Cl, imidazole
2) TBAF/THF
OH
OH
OH
OH
OH
OH
OH
HBr
PBr3
PBr3
SOCl2
OTs
OTf
OMs
OTBDMS
OH
Br
Br
Br
Br
Br
Cl
20
6
5
4
3
2
1
1
2
3
4
5
OH
OHOH
OH
OH
OH
OH
H2SO4
H2SO4
H2SO4
1) NaOMe
2) pentyl bromide
1) NaOEt
2) hexyl iodide
1) NaH
2)Br
6
5
4
3
2
1
O
1
2
3
H2SO4
4
5
6
5
4
3
2
1
O
1
2
3
4
5
NO REACTION
ONLY PRIMARY WORKS
NO REACTION
ONLY PRIMARY WORKS
O
1
2
3
4
5
O 1
2 3
4 5
6
O
21
OH
OH
OH
H2CrO4
KMnO4, OH-, H2O, Heat
PCC
OH
OH
H
O
O
O
OH
Jones
O
OH O
KMnO4, OH-, H2O, Heat
H2CrO4
OR
OH
H2CrO4
KMnO4, OH-, H2O, Heat
ORNO REACTION
TERTIARY ALCOHOLS
DO NOT OXIDIZE
O
H
O
OH
OCH3
1) NaBH4 or H2/Pd or Na/MeOH
or LAH
2) H3O+
OH
OH
1) NaBH4 or H2/Pd or Na/MeOH
or LAH
2) H3O+
O
O
1) LAH
2) H3O+
1) LAH
2) H3O+
OH
OH
22
H
OMgBr
H3O+
OH
1)
2)
OMgBr
H3O+
OH
1)
2)
OH
OMgBr
H3O+ O
O
1)
2)
OR
OMgBr
H3O+
OH
1)
2)
O
MgBr
H3O+
1)
2)
OHGrignard's attack less-substituted carbon
H
O
H3O+
OH
1)
2)
O
H3O+
OH
1)
2)
OH
O
H3O+ O
O
1)
2)
OR
O
H3O+
O
1)
2)
O
H3O+
1)
2)
OHAlkynide's attack less-substituted carbon
H
O
H3O+
OH
1)
2)
O
H3O+
OH
1)
2)
OH
O
H3O+ O
O
1)
2)
OR
O
H3O+
O
1)
2)
O
H3O+
1)
2)
OHAlkynide's attack less-substituted carbon
H
O
H3O+
OH
1)
2)
O
H3O+
OH
1)
2)
OH
O
H3O+ O
O
1)
2)
OR
O
H3O+
O
1)
2)
O
H3O+
1)
2)
OHAlkynide's attack less-substituted carbon
H
O
H3O+
OH
1)
2)
O
H3O+
OH
1)
2)
OH
O
H3O+ O
O
1)
2)
OR
O
H3O+
O
1)
2)
O
H3O+
1)
2)
OHAlkynide's attack less-substituted carbon
23
g
f
e
d
c
b
a
Br 1) 2 Li/ether
2) CuI
3) heptyl bromideg
f
e
d
c
b
a
1
2
3
4
5
6
7
Br
1) 2 Li/ether
2) CuI
3) phenylbromide
a
b
c
d
a
Br
1) 2 Li/ether
2) CuI
3) Br
HOW DO YOU MAKE THIS?
c
b
a
Br
1) 2 Li/ether
2) CuI
3)
12
34
56
7
Br
c
b
a
2
3
4
5
6
7
1
24
a
b
c
d
b
1) 2 Li/ether
2) CuI
3)
HOW DO YOU MAKE THIS?
Br
Br
Br
1) 2 Li/ether
2) CuI
3)
1) 2 Li/ether
2) CuI
3)
Br
c
d
Br
Br
25
Bromination
Br
Br
Br-
Br-
Br
Br
Br
Br
Br
Conversion to a good leaving group
OH
S
O
O
Cl R
OL
L = Ms, Ts or Tf
HB OL
26
Converstion of alcohol to halide
OH3
Br
PBr3
O
PBr2
Br-
HHOPBr2
This can react twice more with alcohol to
brominate the alcohol
3
OHClS
O
ClCl
O
S
O
ClH
Cl-
O
S
Cl-
O
Cl
N trialkyl amines(such as triethylamine(TEA))
are used to scavenge the HCl that is formed
in this reaction.
27
Oxymercuration
OH
1) HgAcetate/THF/H2O
2) NaOH/NaBH4
HgAcetate = Hg(OCCH3)2
O O
OCCH3 = Ac
MECHANISM
Hg(OAc)2 HgOAc + OAc
HgOAc
!+
!+
H
O
H
HgOAc
O
H
H
H
O
H
HgOAc
O H
other steps
28
Hydroboration
1) BH3:THF
2) H2O2/OH-
OH
H
MECHANISM
BH
H
H
H B H
H
H B
H
B
3
+ enatiomer
H O O
R
R
B
R
O OH
unstable
intermediate
R
B
R
OR
repeat 2x'sRO
B
RO
OR
OH
BRO
OR
OH
OR
BRO
OR
O
O
R
H
ROH
OH
H
=
29
Reduction of ketone/aldehyde
R(H)
O
1) NaBH4
2) H3O+ R(H)
OH
H3B H
R(H)
O
H OH2
Oxidation of alcohol
R(H) R(H)
OOH
[Cr]
Cr
O
O
OOH
H O H
H
R(H)
O
Cr
O
O
HO
HO
H
H2O
H O H
H
R(H)
O
Cr
O
HO
H2OO
R(H)
O
Cr
O
OHO
H
H2O
30
H
BH2
H
R2B O
OH
BH3
O OH
H
O-
H
OH
H
O BR2
H+
OH-
31
Chapter 11 Homework Name: 1. For the reactions on the next two pages, indicate if they are Markovnikov or anti-Markovnikov, syn or anti addition. Also indicate which reactions are regioselective and which are stereospecific.
HCl
Br2
H3O+
HBr/H2O2
1) HgAcetate, THF, H2O
2) NaBH4, NaOH
HBr/CCl4
1) BH3:THF
2) H2O2, OH-
1) Hg(O2CCF3), CH3CH2CH2OH
2) NaBH4, NaOH
Br2/H2O
Cl
Br
Br
OH
Br
Br
Br
OH
OHOH
OCH2CH2CH3
32
Diazomethane
MMPP
1) MMPP
2) HBr
1) MMPP
2) NaBr
OH
OH
OH
CH2I2/Zn(Cu)/diethyl ether
1) MMPP
2) H+
KMnO4, OH-, H2O, cold
1) OsO4, pyridine
2) NaHSO3, H2O
Br2, H2O
O
OH
OH
OH
OH
Br
Br
OH
OH
Br
33
2. Fill in the products for the following reactions.
OH
PBr5
Excess HCl
SOCl2
1) NaH/Tf-Cl
2) NaSH
MMPP
1) TBDMS-Cl
2) BH3:THF
3) H2O2/OH-
4) NaH/CH3I
5) TBAF
6) NaH/TsCl
7) NaOMe/MeOH
1) MMPP
2) TBDMS-Cl
3) NaSH
4) PBr5
5) TBAF
1) MMPP
2) Excess HCl
34
OH Br
Br
O
Br Br
Br
Br
OH
O
OCH3
Br
Br
H3CO
OH
OH
3. Fill in the reagents needed to accomplish these changes.
35
KEY For the reactions on the next two pages, indicate if they are Markovnikov or anti-Markovnikov, syn or anti addition. Also indicate which reactions are regioselective and which are stereospecific.
HCl
Br2
H3O+
HBr/H2O2
1) HgAcetate, THF, H2O
2) NaBH4, NaOH
HBr/CCl4
1) BH3:THF
2) H2O2, OH-
1) Hg(O2CCF3), CH3CH2CH2OH
2) NaBH4, NaOH
Br2/H2O
Cl
Br
Br
OH
Br
Br
Br
OH
OHOH
OCH2CH2CH3
Markovnikov and Regioselective
Markovnikov and Regioselective
Markovnikov and Regioselective
Markovnikov and Regioselective
Markovnikov and Regioselective
Anti-Markovnikov and Regioselective
Mark., Regio, Anti Addition, Stereo.
Anti-Addiction, Stereo.
Anti-Mark., Regio, SYN Addition, Stereo.
36
Diazomethane
MMPP
1) MMPP
2) HBr
1) MMPP
2) NaBr
OH
OH
OH
CH2I2/Zn(Cu)/diethyl ether
1) MMPP
2) H+
KMnO4, OH-, H2O, cold
1) OsO4, pyridine
2) NaHSO3, H2O
Br2, H2O
O
OH
OH
OH
OH
Br
Br
OH
OH
Br
Syn addition, stereospecific
Syn addition, stereospecific
Syn addition, stereospecific
Syn addition, stereospecific
Syn addition, stereospecific
Anti-addition, stereospecific
Mark., Regio, Anti, Stereo.
Anti-Mark., Regio, Anti, Stereo.
Mark., Regio, Anti, Stereo.
37
2. Fill in the products for the following reactions.
OH
PBr5
Excess HCl
SOCl2
1) NaH/Tf-Cl
2) NaSH
MMPP
1) TBDMS-Cl
2) BH3:THF
3) H2O2/OH-
4) NaH/CH3I
5) TBAF
6) NaH/TsCl
7) NaOMe/MeOH
1) MMPP
2) TBDMS-Cl
3) NaSH
4) PBr5
5) TBAF
1) MMPP
2) Excess HCl
Br
Cl
Cl
Cl
SH
Cl
Cl
OH
OH
Br
SH
OH
O
OCH3
38
OH Br
Br
O
Br Br
Br
Br
OH
O
OCH3
Br
Br
H3CO
OH
OH
3. Fill in the reagents needed to accomplish these changes.
HBr
1) NaH, TfCl
2) NaBr
1) NaOCH3
2) Ethyl iodide1)
2) MMPP
OK
1) TBDMS-Cl
2) NaBr
3) NaH, CH3I
4) TBAF
1) TBDMS-Cl
2) HBr
3) NaH, CH3I
4) TBAF
39
Homework Name: 1. Fill in the products of these reactions.
1) MMPP2) NaSH
1) MMPP2) H+
1) MMPP2) HBr
1) Hg(O2CCF3), Propanol 2) NaBH4, NaOH
PBr3
SOCl2
TBDMS-Cl/NaH
HBr
OH
40
2. For the following, fill in the reagents.
OH
OHO
OHOH
OH
OCH3OH
HO
41
3. Show the mechanisms for the following.
Br
HBr/H2O2
OH Br
PBr3
42
OH Cl
SOCl2
1) HgAcetate/THF/H2O
2) NaOH/NaBH4
OH
43
1) BH3:THF
2) NaOH/H2O2
OH
44
Homework KEY 1. Fill in the products of these reactions.
