Ch 18

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  • Topic: Ether, Functional groups, Diethyl ether
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Chapter 18 Ethers & Epoxides; Thiols and Sulfides
Assigned Reading from McMurry: Read Sections 18.1 through 18.9; not responsible for “Focus on … Epoxy Resins & Adhesives, pp. 697-698).

Recommended Problems from McMurry: 18.1a-e;18.18.2;18.3a-d; 18.4; 18.5a-d; 18.6a-b; 18.7a-b; 18.8; 18.9; 18.10; 18.11; 18.12a,b; 18.13a,b; 18.14a-c; 18.16a-f; 18.17; 18.18; 18.19a-c; 18.20; 18.21; 18.22; 18.23a-e; 18.24a-I; 18.25a-f; 18.26a-d; 18.27; 18.28; 18.29ad; 18.30a-e; 18.31; 18.32; 18.33; 18.34; 18.35a-d; 18.36; 18.37; 18.38; 18.39; 18.40a,b; 18.41a-d; 18.42; 18.43; 18.44; 18.45; 18.45; 18.46; 18.47; 18.48; 18.49; 18.51; 18.52; 18.53; 18.54; 18.551-e; 18.56; 18.57; 18.58a-b; 18.59a-b; 18.60; 18.61.

18.1 Names and Properties of Ethers
Method A: Simple ethers; alphabetize if two organic substituents. CH3–CH2–O–CH2–CH3
Diethyl ether

Methyl propyl ether

O

CH3–CH2–CH2–O–CH3

CH3

Methyl phenyl ether

SP 18.01 Provide systematic names for the following ethers.
CH3–CH2–O–CH2–CH2–CH2–CH3

O

SP 18.02 Provide structures for the following systematic names. Systematic name: Isopropyl phenyl ether

Systematic name: Cyclohexyl ethyl ether

Method B: Other functional groups present, ether component is an “alkoxy” substituent. Alkoxy examples: methoxy ─OCH3, ethoxy ─OCH2CH3, propoxy ─OCH2CH2CH3, etc. O C H3

O

CH3

O C H3

para-Dimethoxybenzene

3-Methoxy-1-cyclopentene

SP 18.03 Provide systematic names for the following complex ethers. OCH3
O

CH2CH3

Cl

SP 18.04 Provide structures for the following systematic names. Systematic name: meta-Bromopropoxybenzene

Systematic name: 1-Isopropoxycyclopentene

18.2 Synthesis of Ethers
The Williamson Ether Synthesis

R

+

O

an alkoxide

C

X

R

SN2

an alkyl halide
methyl & 1o best;
X = Cl, Br, I, OTos

O

C

ether product

Example:
O Na +
Sodium phenoxide

CH3

Br

O

CH3

Phenyl methyl ether
(anisole)

+ Na Br

+

X

SP 18.05 Complete the following reactions.

CH3
CH3

C

O Na

+

CH3

I

+ Na I

CH3

CH3
CH3

C
CH3

I

+

Na O

CH3

+ Na I

SP 18.06 Provide the suitable alkoxide and alkyl halide necessary to produce 2-ethoxy-2-methyl butane in good yield.

CH3
CH3

CH2

C

O

CH3

CH2

CH3 + Na Br

8.4 Oxymercuration Intermediates


For laboratory-scale hydration of an alkene




Use mercuric acetate in THF followed by sodium borohydride
Markovnikov orientation
– via mercurinium ion

Alkoxymercuration of Alkenes

General Reaction:

R

C

C

2) NaBH4

H
C

R
Ether

Alkene
RO

Step #1

RO
C

1) Hg(OAc)2, ROH

H g OA c

C

C

Step #2

R

+

HOAc

Markovnikov
addition

SP 18.07 Complete the following reactions by displaying the final major organic product. H
C

1) Hg(OAc)2, CH3OH

H

C

2) NaBH4

H

CH3
CH3

C

C

H

CH3

1) Hg(OAc)2, CH3OH
2) NaBH4

SP 18.08 Specify the alkene and alcohol needed to produce the following ether.

Alcohol

OCH2CH3

1) Hg(OAc)2,
CH3
2) NaBH4

Alkene

18.3 Reactions of Ethers: Acidic Ether Cleavage
General Reaction:
HX
C

O

C

C

OH

+

X

C

(strong acid)
Ether

Alcohol

Alkyl halide

SP 18.09 Predict the product for the following ether-cleavage reaction. CH3
CH3

C

O

CH3

HBr
CH2CH3

18.4 Reactions of Ethers: Claisen Rearrangement
O

OH

1,3 O to C shift
Thermodynamically
more stable

o

250
Allyl phenyl ether
C9H10O

ortho-Allyl phenol
C9H10O

Mechanism (involves six-membered transition state):
1

O

TS
2
3

1

O

2

H

keto-enol

tautomerization
3

O

H

SP 18.10 Predict the structure for the following Claisen rearrangement.

O
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