Chapter 18 l.jpg
Sponsored Links
This presentation is the property of its rightful owner.
1 / 48

Chapter 18 PowerPoint PPT Presentation


  • 251 Views
  • Updated On :
  • Presentation posted in: General

Chapter 18. Ethers and Epoxides; Thiols and Sulfides. Ethers. Definition: Two organic groups bonded to the same oxygen atom Examples:. Diethyl ether. Methyl phenyl ether (Anisole). Tetrahydrofuran (cyclic ether). Naming of Ethers. There are two ways to name it:

Download Presentation

Chapter 18

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Chapter 18

Ethers and Epoxides;

Thiols and Sulfides


Ethers

  • Definition: Two organic groups bonded to the same oxygen atom

  • Examples:

Diethyl ether


Methyl phenyl ether (Anisole)

Tetrahydrofuran (cyclic ether)


Naming of Ethers

There are two ways to name it:

  • Identifying the two organic substituents and adding the word ether

Dimethyl ether


Tert-Butyl methyl ether

Ethyl-phenyl ether


  • If other functional groups are present, the ether part is considered an alkoxy substituent.

Tert-butoxy butane

Para-ethoxy methoxy benzene


1-methoxy-cyclohexene

4-tert-Butoxy-1-cyclohexene


Isopropoxy cyclohexane

p-dimethoxybenzene


  • Physical Properties

  • Soluble in water

  • Boiling point: very low, about 200C

  • R—O—R bonds: tetrahedral bond angle

  • The Oxygen atom is sp3-hybridized


Preparation of Ethers


Symmetrical ethers R-O-R


Mechanism:


Examples


Symmetrical ethersR-O-R’

  • The Williamson Ether Synthesis:


Examples

α-D-Glucose

Α-D-Glucose pentamethyl ether


tert-Butoxide ion

Iodomethane

tert-Butyl methyl ether


Methoxide ion

2-Chloro-2-methylpropane

2-Methylpropene


1) Reaction

  • Alkoxymercuration of Alkenes


2. Mechanism


3. Examples

Styrene

1-Methoxy-1-phenyethane


Reaction of Ethers


  • Acidic Cleavage

    1) Ethers with primary and secondary alkyl groups react by an SN2

Ethyl isopropyl ether

Isopropyl alcohol

Iodoethane


Mechanism


Examples:

Bromoethane

Ethyl phenyl ether

Phenol

2-Ethoxypropanoic acid

Iodoethane

Lactic acid


2) Ethers with a tertiary, benzylic, or allylic group react by an SN1 or E1

E1 reaction

tert-Butyl cyclohexyl ether

Cyclohexanol

2-Methylpropene


Mechanism:


SN1 reaction


Mechanism:


1) Claisen rearrangement is pecific to allyl aryl ethers, Ar-O-CH2CH=CH2

  • Claisen Rearrangement

2) Example:

Phenol

Sodium phenoxide

Allyl phenyl ether

Allyl phenyl ether

0-Allylphenol


3) Mechanism:

Transition state


sECTION 18.7


SECTION 18.8


SECTION 18.9


SECTION 18.10


  • Login