Organic Chemistry 1- Chapter 11

Ethers, Epoxides, and Sulfides

One oxygen atom bonded to two carbon atoms

Ether

True or False:

When naming an ether, select the longest carbon chain as the parent chain, then name the -OR group bonded to it as an alkoxy group

True

A heterocyclic compound containing three atoms is denoted by the ending…

irane

A heterocyclic compound containing four atoms is denoted by the ending…

etane

A heterocyclic compound containing five atoms is denoted by the ending…

olane

A heterocyclic compound containing six atoms is denoted by the ending…

ane

Ethers are ______ polar

Weakly

What two intermolecular interactions do ethers experience?

Dispersion forces and dipole-dipole

B.p. of ethers is much _____ than those of corresponding alcohols

Lower

Ethers are hydrogen bond _________

Acceptors

Ethers are ____ soluble in water than hydrocarbons of comparable molecular weight

More

Ethers are prepared by __________ _____ synthesis, which is an ___ reaction mechanism

Williamson ether; Sn2

Symmetrical ethers can be prepared through dehydration of a(n) _______ in ______ acid

Alcohol; strong

General synthesis of dialkyl ethers by an Sn2 reaction between a haloalkane and an alkoxide ion

Williamson ether synthesis

In a Williamson ether synthesis reaction, the O atom should already be on the ____ substituted carbon

More

For the acid-catalyzed dehydration of alcohols, yields are highest for ___________ ethers formed by unbranched _° alcohols

Symmetrical; 1

The acid-catalyzed dehydration of a 3° alcohol always results in a(n)…

Alkene

True or False:

Alcohols can be added to an alkene to give an ether

True

Ethers are cleaved by __

HX

Ethers are highly ________ and _________

Volatile; flammable

Ethers are great ________ for organic reactions

Solvents

Cleavage of ethers requires a ______ acid and a ____ nucleophile

Strong; good

Cleavage of a 1° and 2° alkyl ether reacts via ___ mechanism

Sn2

Cleavage of a 3° alkyl ether reacts via ___ mechanism

Sn1

Is HCl a good enough nucleophile to cleave an ether?

No

3-membered cyclic ethers

Epoxides

True or False:

Epoxides are much less chemically reactive than ethers

False

Epoxides are synthesized from _______ using peroxycarboxylic acids in a reaction that involved a _-membered ring transition state

Alkenes; 5

What is one of the few epoxides that is synthesized on an industrial scale?

Ethylene oxide

Internal nucleophilic substitution in halohydrins, oxidation of alkenes with peroxycarboxylic acids, and sharpless asymmetric epoxidation are all ways to _________ epoxides

Synthesize

List the following form of synthesizing an epoxide:

1. Treat an alkene with Br2/Cl2 and H2O to form a halohydrin (from chapter 6)

2. Treat the halohydrin with a base to bring about intramolecular displacement of Cl^-

Internal nucleophilic substitution in halohydrins

List three common peroxycarboxylic acid oxidizing agents

MCPBA, MMPP, and peracetic acid

MCPBA, MMPP, and peracetic acid all oxidize an ______ to an _______

Alkene; epoxide

Epoxidation of a trans alkene results in a _____ epoxide

Trans

Epoxidation of a cis alkene results in a ___ epoxide

Cis

MCPBA, MMPP, and peracetic acid oxidation all take place in ________ solvents

Nonpolar

MCPBA, MMPP, and peracetic acid all react with complete _________ of configuration

Retention

List the following form of synthesizing an epoxide:

Oxidation of a C=C bond of a 1° allylic alcohol by tert-butyl hydroperoxide in the presence of (+) or (-)-diethyl tartrate and Ti(OiPr)4

Sharpless asymmetric epoxidation

Symmetric epoxidation creates a…

Racemic mixture

Asymmetric epoxidation creates…

One enantiomer

Sharpless asymmetric epoxidation results in an enantiomerically ____ epoxide

Pure

During Sharpless asymmetric epoxidation, molecules should be drawn so the alcohol is where on the page?

On the bottom right

When the alcohol is drawn in the proper orientation during Sharpless asymmetric epoxidation, (+)-diethyl tartrate delivers to the ______ face of the molecule, resulting in ______ bonds

Bottom; dashed

When the alcohol is drawn in the proper orientation during Sharpless asymmetric epoxidation, (-)-diethyl tartrate delivers to the ___ face of the molecule, resulting in ____ bonds

Top; bold

Epoxides undergo acid-catalyzed ring opening to give _____ upon the addition of _____

Diols; water

Epoxides undergo acid-catalyzed ring opening to give _____-________ upon the addition of ______

Ether-alcohols; alcohol

Acid-catalyzed ring opening with water gives a _____ glycol

Trans

In nucleophilic ring opening of epoxides, the product is _____

Trans

Cyclic polyethers with 12 or more atoms in a ring

Crown ethers

The cavity of a crown ether is _____

Polar

The cavity of a crown ether ________ alkali metals

Solvates

What alkali metal fits almost perfectly into the cavity of 18-crown-6?

Potassium

The outer surface of a crown ether is ________ and hydrocarbon-like

Nonpolar

True or False:

Crown ethers cause ionic compounds to dissolve in nonpolar organic solvents

True

Symmetrical sulfides are made by reacting ____ with _ moles of haloalkane

Na2S; 2

Asymmetrical sulfides are made by reacting ______ salt of a thiol with a __________

Sodium; haloalkane

Sulfides are oxidized with ____

H2O2

Oxidizing a sulfide once makes it a…

Sulfoxide

Oxidizing a sulfide once turns it into a sulfoxide, oxidizing further with NaIO4 turns it into a…

Sulfone