Contributed by:
The highlights are:
1. Reactions of Alcohols, Ethers, Epoxides, and
Sulfur-Containing Compounds
2. Dehydration of alcohols
3. Ring expansion
4. Ring-opening
5. Crown ethers
6. Organometallic compounds
1.
Organic Chemistry
4th Edition
Paula Yurkanis Bruice Chapter 12
Reactions of Alcohols,
Ethers, Epoxides, and
Sulfur-Containing
Compounds
Organometallic
Compounds
Irene Lee
Case Western Reserve University
Cleveland, OH
©2004, Prentice Hall
2.
Alcohols and ethers have to be activated before they
can undergo a substitution or an elimination reaction
Convert the strongly basic leaving group (OH–) into a
good leaving group
Only weakly basic nucleophiles can be used
4.
Secondary and tertiary alcohols undergo SN1 reactions
with hydrogen halides
5.
Primary alcohols undergo SN2 reactions with hydrogen
6.
ZnCl can be used to catalyze certain SN2 reactions
7.
Look out for rearrangement product in the SN1 reaction
of the secondary or tertiary alcohol
8.
Amines do not undergo substitution reactions because
NH2– is a very strong base (a very poor leaving group)
RCH2F > RCH2OH > RCH2NH2
HF H2O NH3
pKa = 3.2 pKa = 15.7 pKa = 36
Protonation of the amine moiety does not solve the
CH3CH2NH3+ + OH- CH3CH2NH2 + H2O
9.
Other Methods for Converting Alcohols
into Alkyl Halides
11.
Converting Alcohols into Sulfonates
12.
Several sulfonyl chlorides are available to activate OH
13.
SN2 of the Activated Sulfonates
14.
Dehydration of Alcohols
To prevent the rehydration of the alkene product, one
needs to remove the product as it is formed
18.
Look out for carbocation rearrangement
20.
Primary Alcohols Undergo Dehydration
by an E2 Pathway
21.
The Stereochemical Outcome of the E1
Dehydration
22.
A Milder Way to Dehydrate an Alcohol
23.
Substitution Reactions of Ethers
Activation of ether by protonation
25.
Reactions of Epoxides
26.
Nucleophilic attack of hydroxide ion on ethylene oxide
and on diethyl ether
28.
When a nucleophile attacks an unprotonated epoxide,
the reaction is a pure SN2 reaction
31.
Epoxides Are Synthetically Useful
Reagents
35.
A crown ether specifically binds certain metal ions or
organic molecules to form a host–guest complex, an
example of molecular recognition
36.
Thiols are sulfur analogs of alcohols
CH3CH2SH CH3CH2CH2SH
ethanethiol 1-propanethiol
CH3
CH3CHCH2CH2SH HSCH2CH2OH
3-methyl-1-butanethiol 2-mercaptoethanol
are stronger acids (pKa = 10) than alcohols
are not good at hydrogen-binding
37.
In protic solvent, thiolate ions are better nucleophiles
than alkoxide ions
CH3OH
38.
The sulfur analogs of ethers are called sulfides or
Sulfur is an excellent nucleophile because its electron
cloud is polarized
39.
Organometallic Compounds
An organic compound containing a carbon–metal bond
40.
Preparation of Organolithium
Compounds
hexane
CH3CH2CH2CH2Br + 2 Li CH3CH2CH2CH2Li + LiBr
1-bromobutane butyllithium
hexane
Cl + 2 Li Li + LiCl
chlorobenzene phenyllithium
41.
Preparation of Organomagnesium
Compounds
42.
Alkyl halides, vinyl halides, and aryl halides can all be
used to form organolithium and organomagnesium
However, these organometallic compounds cannot be
prepared from compounds containing acidic groups
(OH, NH2, NHR, SH, C=CH, CO2H)
44.
A Grignard reagent will undergo transmetallation if it is
added to a metal halide whose metal is more
electropositive than magnesium
45.
Coupling Reactions
Formation of carbon–carbon bonds
48.
The Heck Reaction
O O
CCH3 Pd(PPh3)4 CCH3
+ CH2 CH2
Br (CH3CH2)3N
CH CH2
CH3O
+ Pd(PPh3)4
OTf (CH3CH2)3N
49.
The Stille Reaction
Br Pd(Ph3)4
CH CH2
+ H2C CHSn(CH2CH2CH2CH3)3
THF
OTf Pd(Ph3)4 CH2CH2CH2CH3
+ Sn(CH2CH2CH2CH3)4
THF
50.
The Suzuki Coupling
CH2 CH2
Pd(PPh3)4
Br O CH2CH2CH3
+ CH3CH2CH2 B
O NaOH
H3C Br H3C CH CHCH3
H O Pd(PPh3)4
+ CH3CH C B
O NaOH
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