Orgo 2 Chapter 11
A) (CH3)3CO- + BrCH3
What is the best way to make the ether shown below using a Williamson Ether Synthesis reaction?
B) reduced from Cr+6 to Cr+3
In the chromic acid oxidation of alcohols, the chromium is ________. A) oxidized from Cr+3 to Cr+6 B) reduced from Cr+6 to Cr+3 C) oxidized from Cr+6 to Cr+3 D) reduced from Cr+3 to Cr+6 E) none of the above
B) Reaction A is preferred over reaction B because the smaller methyl iodide would make a better nucleophilic target
In the formation of the following ether, which reaction is preferred and why?
Cl- is a weaker nucleophile than is Br-. The Lewis acid ZnCl2 coordinates with the oxygen of the alcohol to increase its electrophilicity and make it a better leaving group
It is necessary to add ZnCl2 to promote the reaction of HCl with some alcohols while these same alcohols react with HBr quite readily. Explain.
cyclopentane
Provide the name of the major organic product that results when cyclopentanol is subjected to the following sequence of reactions: 1. TsCl, pyridine; 2. LiAlH4.
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Oxidation
Classify the reaction below as an oxidation, a reduction, or neither.
A) oxidation
Classify the reaction below as an oxidation, a reduction, or neither. (CH3)2CHCH2OH → (CH3)2CHCHO
B) reduction
Classify the reaction below as an oxidation, a reduction, or neither. cis-pent-2-ene → pentane
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Complete the following reaction by filling in the necessary reagents.
Extensive resonance stabilization of this ion makes it a particularly good leaving group.
Draw the tosylate ion and explain why it is a particularly good leaving group
C) SOCl2
Given a sample of (R)-2,3-dimethylhexan-3-ol, which of the following would be the best synthesis of (R)-3-chloro-2,3-dimethylhexane? A) HCl/ZnCl2 B) PCl3 C) SOCl2 D) 1. TsCl/Pyridine 2. NaCl E) none of the above
The key is to convert the hydroxyl group into a better leaving group. Methods to do this include protonation, conversion to the tosylate ester, and conversion to the halide.
How can the electrophilicity of hydroxyls be increased? Suggest several specific ways.
Use the Lucas test. When adding the reagents, a second phase would form immediately with tert-butanol while it would be much slower with n-butanol.
How could tell a sample of n-butanol from tert-butanol?
c,d
Mark all the structures below that contain an inorganic ester. (More than one answer is possible.)
ETHANOL
Name the alcohol that would be used in the Fischer esterification synthesis of ethyl propanoate (CH3CH2O2CCH2CH3).
No reaction occurs; Tertiary alcohols are resistant to mild oxidation conditions.
Name the product which results when 1-methylcyclohexanol is treated with DMP reagent.
The enzyme alcohol dehydrogenase converts these compounds to toxic substances in the body. If the patient receives intravenous infusions of ethanol, then the ethanol swamps the enzyme and the potentially deadly alcohols pass from the body unoxidized.
Poisonings by methanol and ethylene glycol are relatively common. How are these poisonings treated clinically?
This is a pinacol rearrangement reaction where the most stable carbocation would be formed at the tertiary position in the ring.
Predict the major product of the following dehydration reaction.
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Provide the major organic product of the following
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Provide the major organic product of the following reaction.
(S)-2-iodobutane
Provide the name of the major organic product that results when (R)-2-butyl tosylate is treated with sodium iodide.
2-methyl-2-pentene
Provide the name of the major organic product that results when (R)-2-methyl-3-pentanol is heated with conc. H2SO4.
ethoxycyclopentane
Provide the name of the major organic product that results when cyclopentanol is subjected to the following sequence of reactions: 1. NaH; 2. CH3CH2Br.
cyclopentyl acetate
Provide the name of the major organic product that results when cyclopentanol is treated with acetyl chloride.
a mixture of trans- and cis-1-chloro-4-methylcyclohexanes
Provide the name of the major organic product that results when trans-4-methylcyclohexanol is treated with Lucas reagent
cis-1-chloro-4-methylcyclohexane
Provide the name of the major organic product that results when trans-4-methylcyclohexanol is treated with thionyl chloride.
1) TsCl, pyridine 2) LiAlD4
Provide the necessary reagents for the following conversion
1) H2SO4, Δ 2) BH3∙THF 3) H2O2, NaOH 4) PCC
Provide the reagents necessary to carry out the multistep synthesis shown below
No reaction. Tertiary alcohols are not oxidized by PCC.
Provide the structure of the major organic product in the reaction below.
hexagon with a cho on top right carbon
Provide the structure of the major organic product in the reaction below.
pentagon with double bond of oxygen at point
Provide the structure of the major organic product in the reaction below.
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Provide the structure of the major organic product in the reaction below.
(CH3)3CCH2COH
Provide the structure of the major organic product in the reaction below. (CH3)3CCH2CH2OH →
(CH3)2CHCH2Br
Provide the structure of the major organic product in the reaction below. (CH3)2CHCH2OH
PhCH2CHClCH3
Provide the structure of the major organic product in the reaction below. PhCH2CH(OH)CH3
PhCH2CH2CN
Provide the structure of the major organic product in the reaction below. PhCH2CH2OH →
CH3(CH2)6CHO
Provide the structure of the major organic product that results when 1-octanol is treated with pyridinium chlorochromate.
CH3CH2COCH2CH2CH3
Provide the structure of the major organic product that results when 3-hexanol is treated with sodium dichromate.
(CH3)2CHCH2CH2CH2Br
Provide the structure of the major organic product that results when 4-methyl-1-pentanol is treated with PBr3.
(CH3)2CHO-Na+ + CH3CH2CH2Br
Show the most efficient use of the Williamson ether synthesis to prepare CH3CH2CH2OCH(CH3)2
B) SN2
The Williamson ether synthesis proceeds via an ________ mechanism. A) SN1 B) SN2 C) E1 D) E2 E) none of the above
acetic acid
The enzyme, alcohol dehydrogenase, which is produced by the liver, converts ethanol to ________, a normal body metabolite.
A) SN1
Through what basic mechanism is 1-methylcyclohexanol converted to 1-bromo-1- methylcyclohexane upon treatment with HBr? A) SN1 B) SN2 C) E1 D) E2 E) radical chain
B) ester
What class of organic compound is the major product of the acid catalyzed reaction of an alcohol with a carboxylic acid? A) ether B) ester C) thiol D) nitrile E) sulfonate ester
D) (S)-2-iodopentane
What compound is produced when (R)-pentan-2-ol is treated with TsCl followed by NaI? A) sodium (R)-pent-3-oxide B) sodium (S)-pent-2-oxide C) (R)-2-iodopentane D) (S)-2-iodopentane E) none of the above
A) CH3CH2CH2CH2I
What compound results when 1-butanol is treated with P/I2? A) CH3CH2CH2CH2I B) racemic CH3CH2CHICH3 C) CH3CH2CH2CH2OP(OH)2 D) CH3CH2CH2CH2PI2 E) Primary alcohols don't react with P/I2.
B
What is the expected product of the reaction below
B
What is the major organic product of the following reaction?
1-chlorobutane
What is the major organic product when n-butanol reacts with hydrochloric acid?
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What is the product of the following reaction?
B
What is the product of the reaction shown below?
1) Na2Cr2O7 / H2SO4 2) EtOH / acid catalyst
What reagents are necessary for the following conversion?
1) Cl2, hν 2) NaOEt, heat 3) BH3 4) H2O2, -OH 5) PCC 6) CH3MgBr 7) H2SO4, heat
What series of synthetic steps could be used to carry out the transformation shown below
1) PBr3 or HBr 2) Mg, ether 3) CH3CH2CHO 4) H3O+ 5) PCC or Na2Cr2O7
What series of synthetic steps could be used to carry out the transformation shown below
1) BH3 2) H2O2,-OH 3) PCC
What series of synthetic steps could be used to carry out the transformation shown below?
1) HBr, ROOR 2) NaCN or 1) BH3 2) H2O2, -OH 3) HBr or PBr3 4) NaCN
What series of synthetic steps could be used to carry out the transformation shown below?
1) Hg(OAc)2, CH3CH2OH 2) NaBH4
What series of synthetic steps could be used to carry out the transformation shown below?
1) Br2, hν 2) NaOEt, heat 3) BH3 4) H2O2, -OH 5) PCC
What series of synthetic steps could be used to prepare (CH3)2CHCHO from (CH3)3CH?
1) Mg, ether 2) ethylene oxide 3) HBr or PBr3
What series of synthetic steps could be used to prepare 1-bromopentane from 1- bromopropane?
1) H2O, H+ or BH3; H2O2, -OH or Hg(OAc) 2, H2O; NaBH4 2) Na2Cr2O7, H+ or PCC 3) CH3MgI 4) H3O+
What series of synthetic steps could be used to prepare 1-methylcyclohexanol from cyclohexene?
1) PCC 2) CH3CH2MgBr 3) H3O+
What series of synthetic steps could be used to prepare PhCH(OH)CH2CH3 from
1) PCC 2) CH3CH2CH2MgBr 3) H3O+ or 1) HBr or PBr3 2) Mg, Et2O 3) CH3CH2CHO
What series of synthetic steps could be used to prepare hexan-3-ol from propan-1-ol?
phosphate ester
What type of linkage bonds the individual nucleotides together in DNA?
A) a single enantiomer
When (R)-butan-2-ol is treated with TsCl in pyridine, the product formed is ________. A) a single enantiomer B) a racemic mixture C) a mixture of diastereomers D) an achial compound E) none of the above
The carbocation formed in this reaction is a tertiary carbocation and substitution is too sterically hindered. Elimination is a more facile reaction.
When tert-butanol is heated in sulfuric acid, why is the major product the elimation product and not the ether (substitution product)?
A) benzyl alcohol
Which alcohol reacts most rapidly with the Lucas reagent? A) benzyl alcohol B) methanol C) 2-propanol D) isobutanol
A) nitroglycerin
Which energetic material is a nitrate ester? A) nitroglycerin B) TNT C) RDX D) nitromethane
E) both A and B
Which of the following alcohols undergoes dehydration upon heating with concentrated H2SO4 without carbocation rearrangement? A) 3,3-dimethylpentan-2-ol B) 3-methylpentan-3-ol C) 2-methylhexan-3-ol D) 2-methyl-2-phenylpropan-1-ol E) both A and B
E) both B and C
Which of the following alcohols will give a positive chromic acid test? A) tert-butanol B) cyclohexanol C) pentan-3-ol D) both A and B E) both B and C
A) CO2
Which of the following compounds has carbon in the highest oxidation state? A) CO2 B) CH3C(O)CH3 C) CH3CH2OH D) CH3C(OCH2CH3)3
B) 2, 3, & 4
Which of the following oxidants will convert a primary alcohol to an aldehyde? 1) sodium dichromate /sulfuric acid 3) pyridinium chlorochromate 2) copper oxide 4) dimethylsulfoxide, oxalyl chloride A) 3 & 4 B) 2, 3, & 4 C) 3 D) 1, 2, 3, & 4 E) none of the above
D) n-butanol 1. H2SO4/heat 2. Hg(OAc)2 (aq) 3. NaBH4 E) 2-methylcycloxexanol 1. H2SO4/heat 2. OsO4/H2O2 3. H2SO4/heat
Which of the following reaction series will result in the formation of a new secondary (2°) alcohol from the beginning alcohol listed at the top? A) Ethanol 1. Na° 2. CH3CH2I B) t-butyl alcohol 1. K2Cr2O7/acetic acid 2. CH3-MgBr 3. H3O+ C) 2-propanol 1. K2Cr2O7/acetic acid 2. CH3-MgBr 3. H3O+ D) n-butanol 1. H2SO4/heat 2. Hg(OAc)2 (aq) 3. NaBH4 E) 2-methylcycloxexanol 1. H2SO4/heat 2. OsO4/H2O2 3. H2SO4/heat
E) 1. TsCl/pyridine 2. LiAlH4
Which of the following reactions or series of reactions would reduce 3-methylbutan-2-ol into 2-methylbutane? A) 1. TsCl/pyridine 2. conc. KMnO4 B) 1. NaOCH3 2.. H2SO4/heat C) 1. pyridinium chlorochromate 2. ZnCl2/HCl D) 1. ZnCl2/HCl 2. t-butoxide/t-butanol E) 1. TsCl/pyridine 2. LiAlH4
E) both A and D
Which of the following reagents can be used to convert cyclopentanol to cyclopentane? A) TsCl, pyridine followed by LiAlH4 B) Na2Cr2O7, H2SO4 C) NaBH4 followed by H3O+ D) H2SO4, heat followed by H2, Pt E) both A and D
D) KCl
Which of the following reagents is not typically viewed as an oxidizing agent? A) Cl2 B) KMnO4 C) O2 D) KCl E) H2O2
B) pyridinium chlorochromate
Which of the following reagents is the best choice for oxidizing a primary alcohol to an aldehyde? A) H2CrO4 B) pyridinium chlorochromate C) Na2Cr2O7, H2SO4 D) KMnO4 E) LiAlH4
D) All reagents will work
Which reagent could be used to perform the following reaction? A) NaOCl/TEMPO B) Swern Oxidation C) DMP (periodane) reagent D) All reagents will work
D) P / I2
Which reagent would be best suited to induce the following transformation? A) I2 B) HI C) NaI D) P / I2
C) 1. SOCl2 2. Mg 3. CH3CHO
Which set of reagents will best convert 2,2-dimethylpropan-1-ol (neopentyl alcohol) to 4,4- dimethylpentan-2-ol? A) 1. HCl 2. Mg 3. CH3CHO 4. H3O+ B) 1. HCl, ZnCl2 2. Mg 3. CH2O 4. H3O+ C) 1. SOCl2 2. Mg 3. CH3CHO 4. H3O+ D) 1. HCl, ZnCl2 2. Mg 3. CH3CHO 4. H3O+
1-methylcyclopentanol; goes via the more stable 3° carbocation
Which undergoes dehydration using concentrated H2SO4 faster, cyclopentanol or 1- methylcyclopentanol? Explain briefly
The hydroxide ion, a relatively strong base, is a very poor leaving group.
Why are alcohols unreactive toward nucleophilic substitution reactions?
