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Chapter 10. Reactions of Alcohols, Amines, Ethers, and Epoxides

Learning objectives:

1. Provide both IUPAC and common (when applicable) names for alcohols and ethers.

2. Describe the physical properties of alcohols, amines and ethers.

3. Remember the approximate pKa values for alcohols, water, and hydronium ion.

4. Write the reaction equations of alcohols reacting with active metals, such as Li, Na,

and K.

5. Write the reaction and electron-pushing (arrow-pushing) mechanism for the conversion

of alcohols to alkyl halides.

6. Write the reaction and electron-pushing (arrow-pushing) mechanism for the conversion

of alcohols to alkenes, and explain the regioselectivity when applicable.

7. Write the oxidation from primary alcohol to aldehydes then to carboxylic acids, and

recognize the difference in using chromic acid versus PCC.

8. Know the reactions of amines and properties of ammonium salts.

9. Write the ring-opening of epoxides in acidic and basic conditions, and explain the

observed stereochemistry of the products.

10. Differentiate primary, secondary, and tertiary alkyl alcohols and amines.

Sections to be covered:

10.1 The Nomenclature of Alcohols

10.2 Reactions of Alcohols

10.3 Reactions of Amines

10.4 Reactions of Ethers

10.1 The Nomenclature of Alcohols

A. Structure and classification

ROH

Know how to classify primary (1°), secondary (2°) and tertiary (3°) alcohols.

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B. Nomenclature

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OH

OH

HO

OH

OH

OH

HO

C. Physical Properties

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D. Acidity of Alcohols

Know the estimated pKa of water, hydronium (H3O+), methanol and ethanol.

E. Self-assessment Questions

Can you provide IUPAC and common (when applicable) names for alcohols?

Can you describe the physical properties of alcohols?

Can you remember the approximate pKa values for alcohols, water, and

hydronium ion?

Can you differentiate primary, secondary, and tertiary alkyl alcohols?

10.2 Reactions of Alcohols

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A. Reaction with Active Metals (Preparation of Alkoxides)

2·CH3OH + 2·Na → 2·CH3O- + H2

B. Conversion to Haloalkanes

R OHHX

R X X = Cl, Br, I

(i) Examples

OH

+ H Cl

Cl

+ H OH

OH

H Br+

(ii) Mechanism (SN1 and SN2)

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C. Acid-Catalyzed Dehydration to Alkenes (-elimination)

(i) General Mechanism

(ii) Relative ease of dehydration

(iii) Dehydration and Zaitsev’s rule

H2SO4heating

OH

+ +

74% 23% 3%

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(iv) Comparison with Hydration Reaction of Alkenes

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D. Oxidation of alcohols

(i) General Reactions

H

HC

OH

C[O]

HC

O

C[O]

OHC

O

C

H

RC

OH

C[O]

RC

O

C

(ii) Examples

OH

OH

CrO3H2SO4

Na2Cr2O7H2SO4

H2CrO4

OH

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O

O

CrO3H2SO4

Na2Cr2O7H2SO4

OHPCC

E. Self-assessment Questions

Can you write the reaction equations of alcohols reacting with active metals,

such as Li, Na, and K?

Can you write the reaction and electron-pushing (arrow-pushing) mechanism

for the conversion of alcohols to alkyl halides?

Can you write the reaction and electron-pushing (arrow-pushing) mechanism

for the conversion of alcohols to alkenes, and explain the regioselectivity when

applicable?

Can you write the oxidation from primary alcohol to aldehydes then to

carboxylic acids, and recognize the difference in using chromic acid versus

PCC?

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10.5 Reactions of Amines

A. Nomenclatures and Classification of Amines

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B. Structure of Amines

C. Acidity of amines

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D. Common Roles of Amines and Properties of Ammonium Salts

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E. Heterocyclic Amines and Plant Alkaloids

F. Self-assessment Questions

Can you provide IUPAC and common (when applicable) names for amines?

Can you describe the physical properties of amines?

Can you remember the approximate pKa values for amines and ammonium

ion?

Can you differentiate primary, secondary, and tertiary alkyl amines?

Can you describe the common roles of amines and properties of ammonium

salts?

10.4 Reactions of Ethers

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A. Structure and Nomenclature of Ethers

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B. Ring-Opening of Epoxides

(i) Stereoselectivity

OH+

H2O

OH

OH

+

OH

OH

(iI) Regioselectivity

Ring-opening in acidic condition

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Ring-opening in basic condition

C. Self-assessment Questions

Can you provide IUPAC and common (when applicable) names for ethers?

Can you describe the physical properties of ethers?

Can you write the ring-opening of epoxides in acidic and basic conditions, and

explain the observed stereochemistry of the products?