Download Chemistry 262 Quiz 2 Winter 2017 The following

Chemistry 262
Quiz 2
Winter 2017
The following practice quiz covers Chapter 10 in Loudon & Parise’s Organic
Chemistry, 6th ed. and contains 24 questions. Wednesday’s quiz will also contain 24
questions, valued at 1.25 point/question, as well as 3 bonus questions valued at 2
points each
Name: _________________________________________________________
ALCOHOL AND THIOL ACID BASE CONSIDERATIONS
1. Which of the following has the highest pKa value in aqueous solution?
a. n-butanol
b. sec-butyl alcohol
c. isobutyl alcohol
d. tert-butyl alcohol
e. mercaptobutane (butane-1-thiol)
ALCOHOL AND THIOL ACID BASE CONSIDERATIONS
2. Which of the following has the lowest pKa value in aqueous solution?
a. n-butanol
b. sec-butyl alcohol
c. isobutyl alcohol
d. tert-butyl alcohol
e. mercaptobutane (butane-1-thiol)
ALCOHOL AND THIOL ACID BASE CONSIDERATIONS
3. Which of the following would be substantially (> 10 %) deprotonated by sodium
phenoxide (PhONa)
a. tert-butyl alcohol
b. Cyclohexanone
c. Ethanethiol
d. Hydrogen cyanide
e. More than one of the above
DEHYDRATION OF ALCOHOLS
4. What is the expected outcome when 3-methyl-2-butanol is heated in concentrated
H2SO4?
a. 3-methyl-2-butanesulfonic acid
b. 3-methyl-1-butene
c. 2-methyl-1-butene
d. 2-methyl-2-butene
e. (c) and (d) are equally likely
DEHYDRATION OF ALCOHOLS
5. The reaction between 2-methyl-2-pentanol and HBr to yield 2-methyl-2-pentene is
probably
a. an SN1-type reaction involving the protonated alcohol as the substrate
b. an SN2-type reaction involving the protonated alcohol as the substrate
c. an E1-type reaction involving the protonated alcohol as the substrate
d. an E2-type reaction involving the protonated alcohol as the substrate
e. an epoxidation reaction
REACTION OF ALCOHOLS WITH HYDROGEN HALIDES
6. The reaction between 2-methyl-2-pentanol and HBr to yield 2-bromo-2-methylpentane is
probably?
a. an SN1-type reaction involving the protonated alcohol as the substrate
b. an SN2-type reaction involving the protonated alcohol as the substrate
c. an E1-type reaction involving the protonated alcohol as the substrate
d. an E2-type reaction involving the protonated alcohol as the substrate
e. an epoxidation reaction
BONUS: AN ALTERNATIVE PATHWAY TO DIRECT REARRANGEMENT IS REPETITIVE ELIMINATION AND ADDITION.
SHOW HOW THIS COULD EXPLAIN THE FORMATION OF 2-METHYL-2-PENTENE FROM 4-METHYL-2-PENTANOL IN
AQUEOUS H2SO4:
BASE COMPATABLE ALCOHOL-DERIVED LEAVING GROUPS
7. Which of the following compounds is a tosylate?
O
CH3
O
S O CH3
Br
O
O
S O CH2 CH3
CH3
S O CH3
O
I
II
III
O
CH3
S CH3
O
CH3
O
S
CH3
O
IV
V
a. I
b. II
c. III
d. IV
e. V
BASE COMPATABLE ALCOHOL-DERIVED LEAVING GROUPS
8. cis-3-methylcyclopentanol is treated with CH3SO2Cl in the presence of a base. The
product of the reaction then is allowed to react with KI in methanol. What is the final
product?
a. trans-1-iodo-3-methylcyclopentane
b. cis-1-Iodo-3-methylcyclopentane
c. 1-methylcyclopentene
d. 2-methylcyclopentene
e. 3-methylcyclopentene
BASE COMPATABLE ALCOHOL-DERIVED LEAVING GROUPS
9. Methanesulfonic acid, shown immediately below, is treated in turn with PCl5 and (R)-2butanol. Which of the following Fischer formulas is a stereochemically correct
representation of the final product?
O
CH3
S
OH,
O
H
CH3
MsO
MsO
H
O
CH3
H3C
CH2CH3
CH2CH3
S
H
O
CH2CH3
II
I
O
H3C
III
H
S
O
CH3
O
CH3
H3C
CH2CH3
IV
CH3
S
Cl
O
CH2CH3
V
a. I
b. II
c. III
d. IV
e. V
MODERN METHODS FOR CONVERSION OF ALCOHOLS TO ALKYL HALIDES
10. Consider the conversion of 3-methyl-2-butanol to 2-bromo-3-methylbutane. If a mild
tempertature environment is to be maintained, the best reagent is
a. Conc. HBr
b. Br2
c. NaBr, H2SO4
d. Ph3PBr2
e. HBr, AIBN
MODERN METHODS FOR CONVERSION OF ALCOHOLS TO ALKYL HALIDES
11. Please show the mechanism by which benzyl alcohol is converted to benzyl chloride by
thionyl chloride (SOCl2) in the presence of pyridine (C5H5N)
ORGANIC REDOX REACTIONS
12. List the following compounds in order of increasing oxidation.
CH2Cl2
HCOOH
CH3OH
I
II
III
a. I, II, III
b. III, II, I
c. II, I, III
d. III, I, II
e. I, III, II
ORGANIC REDOX REACTIONS
13. The following transformation would be considered a(n)
CH3Cl
a. Reduction
b. Oxidation
c. Addition
d. Elimination
e. Rearrangement
CH3MgCl
OXIDATION OF ALCOHOLS
14. Which of the reagents listed below would efficiently accomplish the transformation of
2-methyl-3-cyclopentenol into 2-methyl-3-cyclopentenone?
OH
O
?
a. KMnO4(aq, alkaline)
b. CrO3/H2SO4
c. H2, Pt
d. Br2, CCl4
e. Two of the above
OXIDATION OF ALCOHOLS
15. With which of the following compounds will CrO3 in aqueous H2SO4 fail to give a positive
test?
a.
CH3CH2CH2CH2OH
b.
CH3CHCH2CH3
OH
c.
(CH3)3COH
d.
H
CH3CH2CH2C
O
e. More than one of the above
CHEMICAL AND STEREOCHEMICAL GROUP RELATIONSHIPS
16. To use NMR parlance, protons Ha and Hb are said to be
H
Cl
Hb
Ha
a. Identical
b. Enantiotopic
c. Diasterotopic
d. Homotopic
e. Mesotopic
CHEMICAL AND STEREOCHEMICAL GROUP RELATIONSHIPS
17. What is the term best describing the relationship between protons Ha and Hb?
Hb
Ha
a. Homotopic
b. Vicinal
c. Enantiotopic
d. Diastereotopic
e. Isomeric
CHEMICAL AND STEREOCHEMICAL GROUP RELATIONSHIPS
18. A typical proton NMR experiment does not discriminate enantiotopic protons; it will
however distinguish diastereotopic protons. This having been said, how many signals
would you expect for the compound shown below (assuming you had an NMR of sufficient
resolving capacity)?
S
a. 4
b. 5
c. 6
d. 7
e. 8
S
OCTET EXPANSION AND OXIDATION OF THIOLS
19. Which of the following is most oxidized?
a. CH3CH2SH
b. CH3CH2SCH2CH3
c. CH3CH2SSCH2CH3
d. CH3SO2Cl
e. (CH3)2SO
OCTET EXPANSION AND OXIDATION OF THIOLS
20. How many non-bonded pairs of electrons are associated with the sulfur in DMSO
(dimethyl sulfoxide)?
a. 4
b. 3
c. 2
d. 1
e. 0
SYNTHESIS OF ALCOHOLS
21. What principal product(s) would you expect from the following reaction sequence?
CH3
1. BH3-THF
?
2. H2O2, NaOH
CH3
CH3
OH
CH3
O
OH
+
enantiomer
I
a. I
b. II
c. III
d. IV
e. V
H3C
II
CH2OH
OH
+
enantiomer
+
enantiomer
III
IV
V
SYNTHESIS OF ALCOHOLS
22. What principal product(s) would you expect from the following reaction sequence?
CH3
1. Hg(OOCCH3)2
THF, H2O
?
2. NaBH4, NaOH
CH3
CH3
CH2OH
OH
HO CH3
CH3
OH
OH
I
II
III
IV
V
a. I
b. II
c. III
d. IV
e. V
RETROSYNTHETIC ANALYSIS
23. You are tasked with synthesizing 2-phenyl-2-hexanol via a Grignard reaction. What
pair(s) of compounds would make effective starting materials?
a.
O
Br
and
b.
CH3CHCH2Br
O
and
CH3CC6H5
CH3
c.
O
CH3CH2CH2CH2CCH3
d. (a) or (b)
e. (a) or (c)
and C6H5Br
RETROSYNTHETIC ANALYSIS
24. Which of the following synthetic procedures would be employed most effectively to
transform ethanol into ethyl propyl ether?
a.
Ethanol + HBr, then Mg/ether, then H3O+, then NaH, then CH3CH2Br
b.
Ethanol + HBr, then Mg/ether, then HCHO, then H3O+, then NaH, then
CH3CH2Br
c.
Ethanol + CH3CH2CH2OH + H2SO4/140C
d.
Ethanol + NaH, then HCHO, then H3O+, then HBr, then Mg/ether, then
CH3CH2CH2Br
e.
Ethanol + H2SO4/180°C, then CH3CH2CH2Br