1. Ethers

2. Nomenclature Nomenclature of Alcohols (Sec. 4.3F)
Nomenclature of Ethers
Common Names
The groups attached to the oxygen are listed in alphabetical order
IUPAC
Ethers are named as having an alkoxyl substituent on the main chain
Chapter 11

3. Chapter 11 Cyclic ethers can be named using the prefix oxa-
Three-membered ring ethers can be called oxiranes; Four-membered ring ethers can be called oxetanes
Chapter 11

4. Synthesis of Ethers Ethers by Intermolecular Dehydration of Alcohol
Primary alcohols can dehydrate to ethers
This reaction occurs at lower temperature than the competing dehydration to an alkene
This method generally does not work with secondary or tertiary alcohols because elimination competes strongly
The mechanism is an SN2 reaction
Chapter 11

5. Reactions of Ethers
Acyclic ethers are generally unreactive, except for cleavage by very strong acids to form the corresponding alkyl halides
Dialkyl ethers undergo SN2 reaction to form 2 equivalents of the alkyl bromide
Chapter 11

6. Epoxides Epoxides are three-membered ring cyclic ethers
These groups are also called oxiranes
Epoxides are usually formed by reaction of alkenes with peroxy acids
This process is called epoxidation and involves syn addition of oxygen
Chapter 11

7. Reactions of Grignard Reagents with Oxiranes (Epoxides)
Grignard reagents are very powerful nucleophiles and can react with the d+ carbons of oxiranes
The reaction results in ring opening and formation of an alcohol product
Reaction occurs at the least-substituted ring carbon of the oxirane
The net result is carbon-carbon bond formation two carbons away from the alcohol
Chapter 12

8. Chapter 12

9. Introduction
The polarity of a carbon-halogen bond leads to the carbon having a partial positive charge
In alkyl halides this polarity causes the carbon to become activated to substitution reactions with nucleophiles
Carbon-halogen bonds get less polar, longer and weaker in going from fluorine to iodine
Chapter 6

10. Nucleophilic Substitution Reactions
In this reaction a nucleophile is a species with an unshared electron pair which reacts with an electron deficient carbon
A leaving group is substituted by a nucleophile
Examples of nucleophilic substitution
Chapter 6

11. Organic Synthesis: Functional Group Transformations Using SN2 Reactions
Stereochemistry can be controlled in SN2 reactions
Chapter 6