Vollhardt  Capítulo 8 (Álcoois)
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Vollhardt Capítulo 8 (Álcoois)

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53. Outline the best method for preparing each of the following compounds from an appropriate
alcohol.

(a)

O

 (b) CH3CH2CH2CH2COOH (c)
C

H

B
O

 (d)
A

B
CH3CHCCH3

CH3

O

 (e)
B

CH3CH

O

54. Suggest three different syntheses of 2-methyl-2-hexanol. Each route should utilize one of the
following starting materials. Then use any number of steps and any other reagents needed.

(a)

O

 (b)

O

 (c) H

O

55. Devise three different syntheses of 3-octanol starting with (a) a ketone; (b) an aldehyde; (c) an
aldehyde different from that employed in (b).

56. Fill in the missing reagent(s) needed to convert each molecule into the next one pictured in the
synthetic scheme below. If a transformation requires more than one step, number the reagents for
the individual steps sequentially.

H3CBr

A

OH

B

57. Waxes are naturally occurring esters (alkyl alkanoates) containing long, straight alkyl chains.
Whale oil contains the wax 1-hexadecyl hexadecanoate, as shown in the margin. How would you
synthesize this wax, using an SN2 reaction?

58. The reduced form of the coenzyme nicotinamide adenine dinucleotide (NAD1, Chemical High-
light 8-1) is abbreviated NADH. In the presence of a variety of enzyme catalysts, it acts as a
biological hydride donor, capable of reducing aldehydes and ketones to alcohols, according to the
general formula

AB
O OH

RCR RCHRNADH H�
Enzyme

� � NAD��

B
O

CH3(CH2)14CO(CH2)15CH3
1-Hexadecyl hexadecanoate

 C h a p t e r 8 331

 The COOH functional group of carboxylic acids is not reduced. Write the products of the NADH
reduction of each of the molecules below.

(a) CH3CH NADH�
Alcohol dehydrogenaseB

O

(b) CH3CCOH NADH�
Lactate dehydrogenaseB B

OO

2-Oxopropanoic acid
(Pyruvic acid)

Lactic acid

(c) NADH�
Malate dehydrogenase

2-Oxobutanedioic acid
(Oxaloacetic acid)

Malic acid
HOCCH2CCOH

B B B
O OO

59. Reductions by NADH (Problem 58) are stereospecifi c, with the stereochemistry of the product
controlled by an enzyme (see Chemical Highlight 8-1). The common forms of lactate and malate
dehydrogenases produce exclusively the S stereoisomers of lactic and malic acids, respectively.
Draw these stereoisomers.

60. Chemically modifi ed steroids have become increasingly important in medicine. Give
the possible product(s) of the following reactions. In each case, identify the major stereoisomer
formed on the basis of delivery of the attacking reagent from the less hindered side of the substrate
molecule. (Hint: Make models and refer to Section 4-7.)

P r o b l e m s

(a)

H

H

H

H

CH3 CH

CH3

%

%%

≥

≥≥

$

}
HO

A
OCH3

OH

1. Excess CH3MgI
2. H�, H2O

O

(b)

H

H

H

H

CH3

CH3

%

%%

≥

≥≥

O
O

}
HO

1. Excess CH3Li
2. H�, H2O

61. Why do the two reactions shown in Problem 60 both require the use of excess
CH3MgI and CH3Li, respectively? How many equivalents of the organometallic reagents are
needed in each case? What are the products of the reaction at each functionalized site in each
molecule?

Team Problem
62. Your team has been asked to devise a synthesis of the tertiary alcohol 2-cyclohexyl-2-butanol, A.

Your laboratory is well stocked with the usual organic and inorganic reagents and solvents. An
inventory check reveals that there are many appropriate bromoalkanes and alcohols on hand. As
a group, analyze alcohol A retrosynthetically and propose all possible strategic disconnections.
Check the inventory to see if a particular route is feasible in terms of available starting materials.
Then divide the proposed routes evenly among yourselves to evaluate the merits or pitfalls of these
strategies. Write a detailed synthetic plan based on your chosen retrosynthesis for the synthesis of
2-cyclohexyl-2-butanol. Reconvene to defend or reject these plans. Finally, take into consideration
the prices of your starting materials. Which one of your routes to A is the cheapest?

Target Molecule Inventory (Price)

 2-Bromobutane ($57/500 g) Cyclohexanol ($16/kg)
 Bromocyclohexane ($91/kg) 1-Cyclohexylethanol ($106/25 g)
 Bromoethane ($36/kg) Cyclohexylmethanol ($21/25 g)
 Bromomethane ($640/kg) (Bromomethyl)cyclohexane ($137/100 g)
 2-Butanol ($31/kg)

OH

2-Cyclohexyl-2-butanol
A

332 C h a p t e r 8 H y d r o x y F u n c t i o n a l G r o u p : A l c o h o l s

(a) CH3OCCH3
H�, H2OB

O

� COCH3OCH3 (b) CH3OCCH3
B
O

B
O

� HOCCH3CH3OH
H�, H2O

(c) CH3OCH2OH
H2O

B
O

� HCH3OH O OC H

(d)
H2O

B
O

� CH3CO2HCH3OH CH3OCCH3

Preprofessional Problems
63. A compound known to contain only C, H, and O gives the following upon microanalysis (atomic

weights: C 5 12.0, H 5 1.00, O 5 16.0): 52.1% C, 13.1% H. It is found to have a boiling point
of 788C. Its structure is

(a) CH3OCH3 (b) CH3CH2OH (c) HOCH2CH2CH2CH2OH
(d) HOCH2CH2CH2OH (e) none of these

64. The compound whose structure is (CH3)2CHCH2CHCH2CH3
OH

 is best named (IUPAC):

(a) 2-methyl-4-hexanol (b) 5-methyl-3-hexanol
(c) 1,4,4-trimethyl-2-butanol (d) 1-isopropyl-2-hexanol

65. In this transformation, what is the best structure for “A”?

1. LiAlH4, dry ether
2. H�, H2O (work-up)

A

CH2CH3
CH2CH3

H OH

(a)

O

(b) CH2CH3

CH2CH3

O

(c)

CH2CH3
CH2CH3

O

(d)
CH2CH3

CH2CH3

O

66. Ester hydrolysis is best illustrated by

	Chapter 8: HYDROXY FUNCTIONAL GROUP: Alcoholsnull
	8-1: Naming the Alcohols
	8-2: Structural and Physical Properties of Alcohols
	8-3: Alcohols as Acids and Bases
	8-4: Industrial Sources of Alcohols: Carbon Monoxide and Ethene
	8-5: Synthesis of Alcohols by Nucleophilic Substitution
	8-6: Synthesis of Alcohols: Oxidation - Reduction Relation Between Alcohols and Carbonyl Compounds
	Chemical Highlight 8-1: Biological Oxidation and Reduction
	Chemical Highlight 8-2: The Breath Analyzer Test
	8-7: Organometallic Reagents: Sources of NucleophilicCarbon for Alcohol Synthesis
	8-8: Organometallic Reagents in the Synthesis of Alcoh
	8-9: Complex Alcohols: An Introduction to SyntheticStrategy
	Chemical Highlight 8-3: Transition Metal-Catalyzed Cross-Coupling Reaction
	Chapter Integration Problems
	New Reactionsnull
	Important Concepts
	Problems