Alcohols & Thiols & Ethers

1
Alcohols Thiols Ethers
Chapter 11
Chapter 10

• Sources
• Structure, Nomenclature, Properties
• Acidity and Basicity
• Rx with active metals
• Conversion to R-X, inorganic acid halides
• Rxs with HX SN1/SN2, sulfonates
• Dehydration of alcohols
• Oxidation of 1o and 2o alcohols
• Oxidation of glycols
• Pinacol Thiols/Sulfur chemistry - skip

6, 31, ss34
2
sources nomenclature (alcohol ethers) properties
reactions acid base active metal
substitution oxidation
3
Preparation of alcohols - (review)
4
sources nomenclature (alcohol ethers) properties
reactions acid base active metal
substitution oxidation
5
Nomenclature alcohols ethers

• IUPAC names alcohol sp3C-OH
• -longest chain that contains the -OH root
• -OH gp lowest number
• - suffix -e to -ol

ether R-O-R sp3C, sp2C, spC in R R bonded to
O -always subsituent - -prefix, alkoxy
(special ethers ,-epoxy)
1-ethoxy-2-butanol
6
Epoxides - 11 - special ethers
Nomenclature - ,-epoxy (substituent) or oxirane
ether acetylene alcohol
,-epoxy--pentyn--ol
(4S)-4,5-epoxy-2-pentyn-1-ol
7
Nomenclature-Alcohols

• IUPAC names
• Longest chain that contains the -OH root
• Give -OH group lowest number
• Change suffix -e to -ol
• (S)-2-methyl-1-butanol

8
Structure - Alcohols
Alcohol functional group -OH group bonded to an
sp3 hybridized carbon bond angles 109.5
H
H
H
C
O
9
Physical Properties
Hydrogen bonding H bonded to an electronegative
atom (F, O, or N)
Hydrogen bond weak ( 5 kcal/mol)
10
Physical Properties

• ethanol dimethyl ether - constitutional isomers
  but weak hydrogen bonds have dramatic effects

hydrogen bonds no hydrogen bonds
11
Quiz Name___________________________
seat_____
Write a reaction equation that represents one of
the source of alcohols.
12
Reactions
alcohols acid base indirect
substitution indirect ?-elimination active
metals oxidation
ethers base indirect substitution indirect
?-elimination
epoxides substitution, indirect direct
13
Acidity of Alcohols

• weak acids

conjugate bases strong
14
Acidity of Alcohols
15
Acidity of Alcohols
Acidity ? on stabilization and solvation
electron donation destabilize alkoxides
Steric BULK
decreases solvation
16
alcohols rx with metals

• Alcohols Li, Na, K (active metals)
• form metal alkoxides

metal alkoxide sodium methoxide
17
rx with metals
sodium cyclohexoxide
18
basicity of alcohols/ethers
weak Lewis base (water-like)
oxonium ion
R H or alkyl
19
Alcohols/Ethers indirect Substitution (with HX)
3 alcohols (ethers) react very rapidly with HCl,
HBr, HI.
1alcohols/ethers are unreactive under these
conditions
R H or alkyl
20
indirect Substitution (with HX)

• 2 alcohols HBr (or HI )

racemization, rearrangement, olefins
21
2o or 3o ROH/ROR with HX - SN1
racemization, rearrangement, olefins
R H or alkyl
22
1o ROH/ROR with HI or HBr - SN2

• X(-) displace

R H or alkyl
23
indirect Substitution (with SOCl2)
24
indirect Substitution (with PBr3)
25
indirect Substitution
R H, alkyl
26
alcohols - alkyl sulfonates, good Lgp
27
alkyl sulfonates (sulfonate ester)
good leaving group for Sn2 rx
28
alkyl sulfonates
prep
29
alkyl sulfonates
prep
30
dehydration of ROH/-HOR of ROR
1 alcohols (ethers) with H2SO4 or H3PO4
R H or alkyl
31
Dehydration of ROH (-OR of ethers)

• Mechanism - same forward or reverse.
• alkene addition and ?-elimination compete

32
Pinacol Rearrangement
This section out rearrangement under
dehydration conditions
33
sources nomenclature properties
reactions acid base active metal
substitution oxidation
34
Oxidation
35
Oxidation 1 ROH

• Pyridinium chlorochromate (PCC)
• pyridine CrO3 Cr(VI) HCl

PCC converts 1 alcohols to aldehydes and 2o
alcohols to ketones
36
Oxidation
aldehyde
acid
ketone
NR (no reaction)
37
?-elimination of H and chromate
38
Oxidation 1 ROH
hydrate
hydrate
39
Oxidation 1o and 2o ROH
40
Oxidation of Glycols with H5IO6 (or HIO42H2O)
acyclic or cis-1,2 cyclic diols
41
Oxidation of Glycols with H5IO6 (or HIO42H2O)
11
42
OsO4 / HIO4 equivalent to O3/red.
43
Oxidation of Glycols with H5IO6 (or HIO42H2O)
mechanism
44
Oxidation of Glycols with H5IO6 (or HIO42H2O)
10
45
Oxidation of Glycols with H5IO6 (or HIO42H2O)
10
46
How does one make butanal from 1-bromobutane?
47
(No Transcript)
48
future chapter chemistry
Chapter 15
49
sources nomenclature properties reactions
acid base active metal substitution oxidation