CHE-300
Review
nomenclature
syntheses
reactions
mechanisms
Alkanes
Alkyl halides
Alcohols
Ethers
Alkenes
conjugated dienes
Alkynes
Alicyclics
Epoxides
Alkanes
Nomenclature
Syntheses
1. reduction of alkene (addition of hydrogen)
2. reduction of an alkyl halide
a) hydrolysis of a Grignard reagent
b) with an active metal and acid
3. Corey-House Synthesis
Reactions
1. halogenation
2. combustion (oxidation)
3. pyrolysis (cracking)
Alkanes, nomenclature
CH3CH2CH2CH2CH2CH3
(n-hexane)
n-hexane
CH3
CH3CH2CHCH2CH3
(no common name)
3-methylpentane
CH3
CH3CHCHCH3
CH3
(no common name)
2,3-dimethylbutane
CH3
CH3CHCH2CH2CH3
(isohexane)
2-methylpentane
CH3
CH3CCH2CH3
CH3
(neohexane)
2,2-dimethylbutane
Alkanes, syntheses
1. Addition of hydrogen (reduction).
| |
—C=C—
+
H2
+
Ni, Pt, or Pd
|
|
 —C—C—
|
|
H H
Requires catalyst.
CH3CH=CHCH3
2-butene
+ H2, Ni  CH3CH2CH2CH3
n-butane
2. Reduction of an alkyl halide
a) hydrolysis of a Grignard reagent (two steps)
i) R—X + Mg  RMgX
(Grignard reagent)
ii) RMgX + H2O  RH + Mg(OH)X
SB
SA
WA
WB
CH3CH2CH2-Br + Mg  CH3CH2CH2-MgBr
n-propyl bromide
n-propyl magnesium bromide
CH3CH2CH2-MgBr + H2O  CH3CH2CH3 + Mg(OH)Br
propane
b) with an active metal and an acid
R—X + metal/acid  RH
active metals = Sn, Zn, Fe, etc.
acid = HCl, etc. (H+)
CH3CH2CHCH3 + Sn/HCl  CH3CH2CH2CH3 + SnCl2
Cl
sec-butyl chloride
n-butane
CH3
CH3
CH3CCH3 + Zn/H+  CH3CHCH3 + ZnBr2
Br
tert-butyl bromide
isobutane
3. Corey-House Synthesis
CH3
CH3
CH3
CH3CH-Br + Li  CH3CH-Li + CuI  (CH3CH)2-CuLi
isopropyl bromide
CH3
CH3
(CH3CH)2-CuLi + CH3CH2CH2-Br  CH3CH-CH2CH2CH3
2-methylpentane
(isohexane)
mechanism = SN2
Note: the R´X should be a 1o or methyl halide for the best yields
of the final product.
Alkanes, reactions
1. Halogenation
R-H + X2, heat or hv  R-X + HX
a) heat or light required for reaction.
b) X2: Cl2 > Br2  I2
c) yields mixtures 
d) H: 3o > 2o > 1o > CH4
e) bromine is more selective
f) free radical substitution
CH3CH2CH2CH3 + Br2, hv  CH3CH2CH2CH2-Br
n-butane
n-butyl bromide
+
CH3CH2CHCH3
Br
sec-butyl bromide
CH3
CH3
CH3CHCH3 + Br2, hv  CH3CHCH2-Br
isobutane
2%
<1%
isobutyl bromide
+
CH3
CH3CCH3
Br
tert-butyl bromide
99%
98%
Alkyl halides
nomenclature
syntheses
1. from alcohols
a) HX
b) PX3
2. halogenation of certain alkanes
3. addition of hydrogen halides to alkenes
4. addition of halogens to alkenes
5. halide exchange for iodide
reactions
1. nucleophilic substitution
2. dehydrohalogenation
3. formation of Grignard reagent
4. reduction
Alkyl halides, nomenclature
CH3
CH3CHCH2CHCH3
Br
2-bromo-4-methylpentane
2o
CH3
Cl-CHCH2CH3
sec-butyl chloride
2-chlorobutane
2o
CH3
CH3CCH3
I
tert-butyl iodide
2-iodo-2-methylpropane
3o
Alkyl halides, syntheses
1. From alcohols
a) With HX
R-OH
+
HX

R-X
+
H2O
i) HX = HCl, HBr, HI
ii) may be acid catalyzed (H+)
iii) ROH: 3o > 2o > CH3 > 1o (3o/2o – SN1; CH3/1o – SN2)
iv) rearrangements are possible except with most 1o ROH
CH3CH2CH2CH2-OH + NaBr, H2SO4, heat 
n-butyl alcohol
(HBr)
n-butyl bromide
1-butanol
CH3
CH3CCH3
OH
CH3CH2CH2CH2-Br
1-bromobutane
+ HCl
tert-butyl alcohol
2-methyl-2-propanol
CH3-OH
methyl alcohol
methanol
+

CH3
CH3CCH3
Cl
tert-butyl chloride
2-chloro-2-methylpropane
HI, H+,heat  CH3-I
methyl iodide
iodomethane
…from alcohols: b) PX3
i) PX3 = PCl3, PBr3, P + I2
ii) ROH: CH3 > 1o > 2o
iii) no rearragements
CH3CH2-OH
+ P, I2 
CH3CH2-I
ethyl alcohol
ethyl iodide
ethanol
iodoethane
CH3
CH3CHCH2-OH
isobutyl alcohol
2-methyl-1-propanol
+ PBr3
CH3
 CH3CHCH2-Br
isobutyl bromide
1-bromo-2-methylpropane
2. Halogenation of certain hydrocarbons.
R-H
+ X2, Δ or hν

R-X
+ HX
(requires Δ or hν; Cl2 > Br2 (I2 NR); 3o>2o>1o)
yields mixtures!  In syntheses, limited to those
hydrocarbons that yield only one monohalogenated
product.
CH3
CH3CCH3
CH3
+ Cl2, heat 
neopentane
2,2-dimethylpropane
CH3
CH3CCH2-Cl
CH3
neopentyl chloride
1-chloro-2,2-dimethylpropane
5. Halide exchange for iodide.
R-X
+ NaI, acetone 
R-I + NaX 
i) R-X = R-Cl or R-Br
ii) NaI is soluble in acetone, NaCl/NaBr are insoluble.
CH3CH2CH2-Br
+
NaI, acetone 
CH3CH2CH2-I
n-propyl bromide
n-propyl idodide
1-bromopropane
1-idodopropane
iii) SN2
R-X should be 1o or CH3
Reactions of alkyl halides:
1. Nucleophilic substitution
R-X
Best with 1o or CH3!!!!!!
+ :Z-  R-Z + :X-
2. Dehydrohalogenation
R-X
+ KOH(alc)  alkene(s)
3. Preparation of Grignard Reagent
R-X
+ Mg

RMgX

RMgX
4. Reduction
R-X
+ Mg
R-X
+ Sn, HCl

R-H
+ H2O

R-H
1. Nucleophilic substitution
R-X + :OH-
 ROH
+ :X-
alcohol
R-X + H2O
 ROH
+ HX
alcohol
R-X + :OR´-

R-O-R´ + :X-
ether
 R-CCR´ + :X-
alkyne
R-X + :I-

iodide
R-X + :CN-
 R-CN
+ :X-
nitrile
R-X + :NH3

+ HX
primary amine
R-X +
-:CCR´
R-I
R-NH2
+ :X-
R-X + :NH2R´  R-NHR´ + HX
R-X + :SH-
 R-SH
R-X + :SR´

+ :X-
R-SR´ + :X-
Etc.
Best when R-X is CH3 or 1o! SN2
secondary amine
thiol
thioether
2. dehydrohalogenation of alkyl halides
|
|
— C — C — + KOH(alc.) 
|
|
H X
a)
b)
c)
d)
e)
f)
g)
h)
RX: 3o > 2o > 1o
no rearragement 
may yield mixtures 
Saytzeff orientation
element effect
isotope effect
rate = k [RX] [KOH]
Mechanism = E2
| |
—C=C—
+ KX + H2O
CH3CHCH3
Br
+ KOH(alc) 
CH3CH=CH2
isopropyl bromide
propylene
CH3CH2CH2CH2-Br
+ KOH(alc)
n-butyl bromide
CH3CH2CHCH3
Br
sec-butyl bromide

CH3CH2CH=CH2
1-butene
+ KOH(alc) 
CH3CH2CH=CH2
1-butene 19%
+
CH3CH=CHCH3
2-butene 81%
3. preparation of Grignard reagent
CH3CH2CH2-Br + Mg  CH3CH2CH2-MgBr
n-propyl bromide
n-propyl magnesium bromide
4. reduction
CH3CH2CH2-Br + Mg  CH3CH2CH2-MgBr
CH3CH2CH2-MgBr + H2O  CH3CH2CH3 + Mg(OH)Br
propane
CH3CH2CHCH3 + Sn/HCl  CH3CH2CH2CH3 + SnCl2
Cl
sec-butyl chloride
n-butane
Alcohols
nomenclature
syntheses
1. oxymercuration-demercuration
2. hydroboration-oxidation
3.
4. hydrolysis of some alkyl halides
reactions
1. HX
2. PX3
3. dehydration
4. as acids
5. ester formation
6. oxidation
Alcohols, nomenclature
CH3
CH3CHCH2CHCH3
OH
4-methyl-2-pentanol
2o
CH3
CH3CCH3
OH
tert-butyl alcohol
2-methyl-2-propanol
3o
CH3
HO-CHCH2CH3
CH3CH2CH2-OH
sec-butyl alcohol
2-butanol
2o
n-propyl alcohol
1-propanol
1o
Alcohols, syntheses
1. oxymercuration-demercuration:
a) Markovnikov orientation.
b) 100% yields. 
c) no rearrangements 
CH3CH2CH=CH2 + H2O, Hg(OAc)2; then NaBH4 
CH3CH2CHCH3
OH
2. hydroboration-oxidation:
Anti-Markovnikov orientation. 
•
100% yields. 
•
no rearrangements 
CH3CH2CH=CH2 + (BH3)2; then H2O2, NaOH 
CH3CH2CH2CH2-OH
Reaction of alcohols
1. with HX:
R-OH
a) HX:
+ HX

R-X
+
H2O
HI > HBr > HCl
b) ROH: 3o > 2o > CH3 > 1o
SN1/SN2
c) May be acid catalyzed
d) Rearrangements are possible except with most 1o alcohols.
CH3CH2CH2CH2-OH + NaBr, H2SO4, heat 
n-butyl alcohol
(HBr)
n-butyl bromide
1-butanol
CH3
CH3CCH3
OH
CH3CH2CH2CH2-Br
1-bromobutane
+ HCl
tert-butyl alcohol
2-methyl-2-propanol
CH3-OH
methyl alcohol
methanol
+

CH3
CH3CCH3
Cl
tert-butyl chloride
2-chloro-2-methylpropane
HI, H+,heat  CH3-I
methyl iodide
iodomethane
2. With PX3
ROH
+ PX3

RX
a) PX3 = PCl3, PBr3, P + I2
b) No rearrangements

c) ROH: CH3 > 1o > 2o
CH3
CH3CCH2-OH
CH3
neopentyl alcohol
+
PBr3

CH3
CH3CCH2-Br
CH3
2,2-dimethyl-1-bromopropane
3. Dehydration of alcohols
|
|
| |
— C — C — acid, heat  — C = C — + H2O
|
|
H
OH
a)
b)
c)
d)
e)
f)
ROH: 3o > 2o > 1o
acid is a catalyst
rearrangements are possible 
mixtures are possible 
Saytzeff
mechanism is E1
CH3CH2-OH
CH3
CH3CCH3
OH
+ 95% H2SO4, 170oC  CH2=CH2
+ 20% H2SO4, 85-90oC 
CH3
CH3C=CH2
CH3CH2CHCH3 + 60% H2SO4, 100oC  CH3CH=CHCH3
OH
+ CH3CH2CH=CH2
CH3CH2CH2CH2-OH + H+, 140oC 
rearrangement!

CH3CH2CH=CH2
+ CH3CH=CHCH3
4) As acids.
a) With active metals:
ROH
+ Na

RONa
+
½ H2 
CH3CH2-OH + K  CH3CH2-O-K+ + H2
b) With bases:
CH4 < NH3 < ROH < H2O < HF
ROH
+ NaOH
 NR!
CH3CH2OH + CH3MgBr  CH4 + Mg(Oet)Br
5. Ester formation.
CH3CH2-OH + CH3CO2H, H+  CH3CO2CH2CH3 + H2O
CH3CH2-OH + CH3COCl 
CH3CO2CH2CH3 +
CH3-OH + CH3SO2Cl  CH3SO3CH3 + HCl
Esters are alkyl “salts” of acids.
HCl
6. Oxidation
Oxidizing agents: KMnO4, K2Cr2O7, CrO3, NaOCl, etc.
Primary alcohols:
CH3CH2CH2-OH + KMnO4, etc.  CH3CH2CO2H
carboxylic acid
Secondary alcohols:
OH
CH3CH2CHCH3
O
+ K2Cr2O7, etc.  CH3CH2CCH3
ketone
Teriary alcohols:
no reaction.
Primary alcohols ONLY can be oxidized to aldehydes:
CH3CH2CH2-OH
+ C5H5NHCrO3Cl 
pyridinium chlorochromate
CH3CH2CHO
aldehyde
or
CH3CH2CH2-OH
+ K2Cr2O7, special conditions

Ethers
nomenclature
syntheses
1. Williamson Synthesis
2. alkoxymercuration-demercuration
reactions
1. acid cleavage
Ethers
R-O-R
or
R-O-R´
Nomenclature:
simple ethers are named:
“alkyl alkyl ether”
“dialkyl ether” if symmetric
CH3CH2-O-CH2CH3
diethyl ether
CH3 CH3
CH3CH-O-CHCH3
diisopropyl ether
1. Williamson Synthesis of Ethers
R-OH
+ Na 
R-O-Na+
 R-O-R´
R´-OH
+
HX
 R´-X
(CH3)2CH-OH + Na  (CH3)2CH-O-Na+
+
CH3CH2CH2-OH + HBr  CH3CH2CH2-Br
 CH3CH2CH2-O-CH(CH3)2
isopropyl n-propyl ether
note: the alkyl halide is primary! 
CH3CH2CH2-OH + Na  CH3CH2CH2-ONa
+
 CH3CH2CH2-O-CH(CH3)2
(CH3)2CH-OH + HBr  (CH3)2CH-Br
2o
The product of this attempted Williamson Synthesis using a
secondary alkyl halide results not in the desired ether but in an
alkene! 
The alkyl halide in a Williamson Synthesis must beCH3 or 1o!
2. alkoxymercuration-demercuration:
a) Markovnikov orientation.
b) 100% yields. 
c) no rearrangements 
CH3CH=CH2 + CH3CHCH3, Hg(TFA)2; then NaBH4 
OH
CH3 CH3
CH3CH-O-CHCH3
diisopropyl ether
Avoids the elimination with 2o/3o RX in Williamson Synthesis.
Reactions, ethers:
1. Acid cleavage.
R-O-R´
+ (conc) HX, heat 
CH3CH2-O-CH2CH3
+
HBr, heat 
R-X
+ R´-X
2 CH3CH2-Br
Alkenes
nomenclature
syntheses
1. dehydrohalogenation of an alkyl halide
2. dehydration of an alcohol
3. dehalogenation of a vicinal dihalide
4. reduction of an alkyne
reactions
1. addition of hydrogen
8. hydroboration-oxidation
2. addition of halogens
9. addition of free radicals
3. addition of hydrogen halides
10. addition of carbenes
4. addition of sulfuric acid
11. epoxidation
5. addition of water
12. hydroxylation
6. halohydrin formation
13. allylic halogenation
7. oxymercuration-demercuration
14. ozonolysis
15. vigorous oxidation
Alkenes, nomenclature
C3H6 propylene
C4H8 butylenes
CH3CH=CH2
CH3CH2CH=CH2
α-butylene
1-butene
CH3CH=CHCH3
β-butylene
2-butene
CH3
CH3C=CH2
isobutylene
2-methylpropene
*
H3 C
*
CH2CH3
C C
H
CH3
*
H3 C
(3-methyl-cis-2-pentene)
Cl
C C
H
(Z)-3-methyl-2-pentene
(E)-1-bromo-1-chloropropene
Br
*
1. dehydrohalogenation of alkyl halides
|
|
— C — C — + KOH(alc.) 
|
|
H X
a)
b)
c)
d)
e)
f)
g)
h)
RX: 3o > 2o > 1o
no rearragement 
may yield mixtures 
Saytzeff orientation
element effect
isotope effect
rate = k [RX] [KOH]
Mechanism = E2
| |
—C=C—
+ KX + H2O
CH3CHCH3
Br
+ KOH(alc) 
CH3CH=CH2
isopropyl bromide
propylene
CH3CH2CH2CH2-Br
+ KOH(alc)
n-butyl bromide
CH3CH2CHCH3
Br
sec-butyl bromide

CH3CH2CH=CH2
1-butene
+ KOH(alc) 
CH3CH2CH=CH2
1-butene 19%
+
CH3CH=CHCH3
2-butene 81%
2. dehydration of alcohols:
|
|
| |
— C — C — acid, heat  — C = C — + H2O
|
|
H
OH
a)
b)
c)
d)
e)
f)
ROH: 3o > 2o > 1o
acid is a catalyst
rearrangements are possible 
mixtures are possible 
Saytzeff
mechanism is E1
CH3CH2-OH
CH3
CH3CCH3
OH
+ 95% H2SO4, 170oC  CH2=CH2
+ 20% H2SO4, 85-90oC 
CH3
CH3C=CH2
CH3CH2CHCH3 + 60% H2SO4, 100oC  CH3CH=CHCH3
OH
+ CH3CH2CH=CH2
CH3CH2CH2CH2-OH + H+, 140oC 
rearrangement!

CH3CH2CH=CH2
+ CH3CH=CHCH3
3. dehalogenation of vicinal dihalides
|
|
—C—C—
|
|
X
X
+ Zn 
| |
— C = C — + ZnX2
eg.
CH3CH2CHCH2 + Zn
Br Br
 CH3CH2CH=CH2 + ZnBr2
Not generally useful as vicinal dihalides are usually made
from alkenes. May be used to “protect” a carbon-carbon
double bond.
4. reduction of alkyne
Na or Li
NH3(liq)
CH3 H
\
/
C=C
/
\
H
CH3
anti-
trans-2-butene
CH3CCCH3
H2, Pd-C
Lindlar catalyst
H
H
\
/
C=C
/
\
CH3 CH3
cis-2-butene
syn-
Alkenes, reactions
1. Addition of hydrogen (reduction).
| |
—C=C—
+
H2
+
Ni, Pt, or Pd
|
|
 —C—C—
|
|
H H
a) Requires catalyst.
b) #1 synthesis of alkanes
CH3CH=CHCH3
2-butene
+ H2, Ni  CH3CH2CH2CH3
n-butane
2. Addition of halogens.
| |
—C=C—
+
X2
|
|
 —C—C—
|
|
X
X
a) X2 = Br2 or Cl2
b) test for unsaturation with Br2
CH3CH2CH=CH2
1-butene
+
Br2/CCl4 
CH3CH2CHCH2
Br Br
1,2-dibromobutane
3. Addition of hydrogen halides.
| |
|
|
— C = C — + HX  — C — C —
|
|
H X
a) HX = HI, HBr, HCl
b) Markovnikov orientation
CH3CH=CH2
CH3
CH2C=CH2
+
+
HI
HBr


CH3CHCH3
I
CH3
CH3CCH3
Br
4. Addition of sulfuric acid.
| |
—C=C—
+
H2SO4
|
|
 —C—C—
|
|
H
OSO3H
alkyl hydrogen sulfate
Markovnikov orientation.
CH3CH=CH2
+
H2SO4

CH3CHCH3
O
O-S-O
OH
5. Addition of water.
|
|
—C=C— +
H2O, H+
|
|
 —C—C—
|
|
H
OH
a) requires acid
b) Markovnikov orientation
c) low yield 
CH3CH2CH=CH2
+
H2O, H+
 CH3CH2CHCH3
OH
6. Addition of halogens + water (halohydrin formation):
| |
|
|
— C = C — + X2, H2O  — C — C — + HX
|
|
OH X
a) X2 = Br2, Cl2
b) Br2 = electrophile
CH3CH=CH2
+
Br2(aq.) 
CH3CHCH2 + HBr
OH Br
7. oxymercuration-demercuration:
a) Markovnikov orientation.
b) 100% yields. 
c) no rearrangements 
CH3CH2CH=CH2 + H2O, Hg(OAc)2; then NaBH4 
CH3CH2CHCH3
OH
With alcohol instead of water:
alkoxymercuration-demercuration:
| |
|
|
— C =C — + ROH, Hg(TFA)2  — C — C —
|
|
OR HgTFA
|
|
— C — C — + NaBH4 
|
|
OR HgTFA
|
|
—C—C—
|
|
OR H
ether
8. hydroboration-oxidation:
a) #2 synthesis of alcohols.
b) Anti-Markovnikov orientation. 
c) 100% yields. 
d) no rearrangements 
CH3CH2CH=CH2 + (BH3)2; then H2O2, NaOH 
CH3CH2CH2CH2-OH
9. Addition of free radicals.
| |
|
|
— C = C — + HBr, peroxides  — C — C —
|
|
H
X
a) anti-Markovnikov orientation.
b) free radical addition
CH3CH=CH2 + HBr, peroxides  CH3CH2CH2-Br
10. Addition of carbenes.
| |
|
|
— C = C — + CH2CO or CH2N2 , hν  — C — C —

•CH2•
| |
—C=C—
 
•CH2•
CH2
“carbene” adds across the
double bond
H2C CHCH3 + CH2N2, hv
H
H2C C CH3
C
H2
11. Epoxidation.
| |
C6H5CO3H
— C = C — + (peroxybenzoic acid) 
|
|
— C— C —
O
epoxide
Free radical addition of oxygen diradical.
| |
—C=C—
 
•O•
PBA
H2C CHCH3
H
H2C C CH3
O
12. Hydroxylation. (mild oxidation)
| |
— C = C — + KMnO4
|
|
 —C—C—
|
|
OH OH
syn
OH
| |
|
|
— C = C — + HCO3H  — C — C — anti
peroxyformic acid
|
|
OH
glycol
cis-2-butene + KMnO2  meso-2,3-dihydroxybutane mp 34o
CH3
H3C
CH3
C C
H
H
H
OH
H
OH
CH3
trans-2-butene + KMnO4  (S,S) & (R,R)-2,3-dihydroxybutane mp 19o
CH3
H3C
H
C C
H
CH3
CH3
H
OH
HO
H
CH3
stereoselective and stereospecific
+
HO
H
H
OH
CH3
13. Allylic halogenation.
| |
|
| |
|
— C = C — C — + X2, heat  — C = C — C — + HX
|
|
H  allyl
X
CH2=CHCH3 + Br2, 350oC  CH2=CHCH2Br + HBr
a) X2 = Cl2 or Br2
b) or N-bromosuccinimide (NBS)
14. Ozonolysis.
| |
|
|
— C = C — + O3; then Zn, H2O  — C = O + O = C —
used for identification of alkenes
CH3
CH3CH2CH=CCH3 + O3; then Zn, H2O 
CH3CH2CH=O
+
CH3
O=CCH3
15. Vigorous oxidation.
=CH2 + KMnO4, heat  CO2
=CHR + KMnO4, heat  RCOOH
=CR2 + KMnO4, heat  O=CR2
carboxylic acid
ketone
CH3CH2CH2CH=CH2 + KMnO4, heat 
CH3CH2CH2COOH + CO2
CH3
CH3
CH3C=CHCH3 + KMnO4, heat  CH3C=O + HOOCCH3
Dienes
nomenclature
syntheses
same as alkenes
reactions
same as alkenes
special: conjugated dienes
1. more stable
2. preferred products of eliminations
3. give 1,2- & 1,4- addition products
(cumulated dienes are not very stable and are rare)
isolated dienes are as you would predict, undergo addition
reactions with one or two moles…
 conjugated dienes are unusual in that they:
1) are more stable than predicted
2) are the preferred products of eliminations
3) give 1,2- plus 1,4-addition products
nomenclature:
CH2=CHCH=CH2
CH3CH=CHCH2CH=CHCH3
1,3-butadiene
conjugated
2-methyl-1,3-butadiene (isoprene)
conjugated
2,5-heptadiene
isolated
isolated dienes: (as expected) 1,5-hexadiene
CH2=CHCH2CH2CH=CH2 + H2, Ni 
CH3CH2CH2CH2CH=CH2
CH2=CHCH2CH2CH=CH2 + 2 H2, Ni  CH3CH2CH2CH2CH2CH3
CH2=CHCH2CH2CH=CH2 + Br2  CH2CHCH2CH2CH=CH2
Br Br
CH2=CHCH2CH2CH=CH2 + HBr  CH3CHCH2CH2CH=CH2
Br
CH2=CHCH2CH2CH=CH2 + 2 HBr  CH3CHCH2CH2CHCH3
Br
Br
conjugated dienes yield 1,2- plus 1,4-addition:
CH2=CHCH=CH2 + H2, Ni  CH3CH2CH=CH2 + CH3CH=CHCH3
CH2=CHCH=CH2 + 2 H2, Ni  CH3CH2CH2CH3
CH2=CHCH=CH2 + Br2  CH2CHCH=CH2 + CH2CH=CHCH2
Br Br
Br
Br
CH2=CHCH=CH2 + HBr 
CH3CHCH=CH2 + CH3CH=CHCH2
Br
Br
peroxides
CH2=CHCH=CH2 + HBr  CH2CH=CHCH3 + CH2CH2CH=CH2
Br
Br
Alkynes
nomenclature
syntheses
1. dehydrohalogenation of vicinal dihalides
2. coupling of metal acetylides with alkyl halides
reactions
1. reduction
2. addition of halogens
3. addition of hydrogen halides
4. addition of water
5. as acids
6. with Ag+
7. oxidation
Alkynes, nomenclature
HCCH
ethyne
acetylene
CH3CH2CCH
1-butyne
ethylacetylene
CH3
HCCCHCH2CH3
3-methyl-1-pentyne
sec-butylacetylene
Synthesis, alkynes:
1. dehydrohalogenation of vicinal dihalides
H
H
|
|
—C—C—
|
|
X
X
H
|
+ KOH  — C = C —
|
X
H
|
—C=C—
|
X
+ NaNH2  — C  C — + NaX + NH3
+ KX + H2O
Synthesis of propyne from propane
Br2, heat
CH3CH2CH3
CH3CH2CH2-Br + CH3CHCH3
Br
KOH(alc)
CH3CHCH2
Br Br
Br2
CH3CH=CH2
KOH
NaNH2
CH3CH CH
Br
CH3C CH
2. coupling of metal acetylides with 1o/CH3 alkyl
halides
R-CC-Na+ + R´X  R-CC-R´ + NaX
a) SN2
b) R´X must be 1o or CH3X
CH3CC-Li+ + CH3CH2-Br  CH3CCCH2CH3
Alkyne, reactions
1. Addition of hydrogen (reduction)
HCCH + 2 H2, Pt  CH3CH3
[ HCCH + one mole H2, Pt  CH3CH3 + CH2=CH2 + HCCH
]
Na or Li
NH3(liq)
—CC—
H2, Pd-C
Lindlar catalyst
H
\
/
C=C
/
\
H
\
/
C=C
/
\
H
H
anti-
syn-
Na or Li
NH3(liq)
CH3 H
\
/
C=C
/
\
H
CH3
anti-
trans-2-butene
CH3CCCH3
H2, Pd-C
Lindlar catalyst
H
H
\
/
C=C
/
\
CH3 CH3
cis-2-butene
syn-
2. Addition of X2
X
X X
|
|
|
— C C— + X2  — C = C — + X2  — C — C —
|
|
|
X
X X
CH3CCH + Br2
Br
Br Br
 CH3C=CH + Br2  CH3-C-CH
Br
Br Br
3. Addition of hydrogen halides:
H
H
X
|
|
|
— C C— + HX  — C = C — + HX  — C — C —
|
|
|
X
H
X
a) HX = HI, HBr, HCl
b) Markovnikov orientation
CH3CCH + HCl  CH3C=CH2
Cl
Cl
+ HCl  CH3CCH3
Cl
4. Addition of water. Hydration.
O
— C  C — + H2O, H+, HgO  — CH2 — C—
H
OH
—C=C—
“enol”
Markovnikov orientation.
keto-enol tautomerism
CH3CH2CCH + H2O, H2SO4, HgO 
1-butyne
O
CH3CH2CCH3
2-butanone
5. As acids.
terminal alkynes only!
a) with active metals
CH3CCH + Na  CH3CC-Na+ + ½ H2 
b) with bases
CH4 < NH3 < HCCH < ROH < H2O < HF
CH3CCH + CH3MgBr  CH4 + CH3C CMgBr
SA
SB
WA
WB
6. Ag+
terminal alkynes only!
CH3CH2CCH + AgNO3  CH3CH2CC-Ag+ 
CH3CCCH3 + AgNO3  NR (not terminal)
formation of a precipitate is a test for terminal alkynes.
7. Oxidation
CH3CH2CCCH3
+
KMnO4  CH3CH2COOH +
HOOCCH3
CH3CCH + hot KMnO4  CH3COOH + CO2
CH3CCCH3 + O3; then Zn, H2O  2 CH3COOH
Alicyclics
nomenclature
syntheses
like alkanes, alkenes, alcohols, etc.
reactions
as expected
exceptions: cyclopropane/cyclobutane
CH3
H3C
CH3
methylcyclopentane
1,1-dimethylcyclobutane
Br
Br
Br
Br
Br
trans-1,2-dibromocyclohexane
Br
3
4
2
5
1
6
cyclopentene
3-methylcyclohexene
1,3-cyclobutadiene
Cycloalkanes, syntheses
A. Modification of a cyclic compound:
H2, Ni
Br
Sn, HCl
Br Mg; then H2O
Cycloalkanes, reactions:
1. halogenation
Cl2, heat
Cl
2. combustion
3. cracking
4. exceptions
+ HCl
exceptions:
H2, Ni, 80o
CH3CH2CH3
Cl2, FeCl3
Cl-CH2CH2CH2-Cl
H2O, H+
CH3CH2CH2-OH
conc. H2SO4
CH3CH2CH2-OSO3H
HI
CH3CH2CH2-I
exceptions (cont.)
+
H2, Ni, 200o 
CH3CH2CH2CH3
Cycloalkenes, syntheses
Cl
OH
KOH(alc)
H+, Δ
cyclohexene
Br
Br
Zn
Cycloalkenes, reactions:
1. addition of H2
8. hydroboration-oxid.
2. addition of X2
9. addition of free radicals
3. addition of HX
10. addition of carbenes
4. addition of H2SO4
11. epoxidation
5. addition of H2O,H+
12. hydroxylation
6. addition of X2 + H2O
13. allylic halogenation
7. oxymerc-demerc.
14. ozonolysis
15. vigorous oxidation
H2, Pt
Br2, CCl4
Br
trans-1,2-dibromocyclohexane
Br
HBr
H2SO4
H2O, H+
Br2 (aq.)
Br
OSO3H
Markovnikov
OH
OH
Br
dimerization
+
HF
+
H2O,Hg(OAc)2
(BH3)2
NaBH4
OH
H2O2, NaOH
Markovnikov
anti-Markovnikov
OH
HBr, perox.
anti-Markovinikov
Br
polymer.
n
CH2CO,hv
PBA
O
OH
KMnO4
cis-1,2-cylohexanediol
OH
OH
HCO3H
OH
trans-1,2-cyclohexanediol
Br
Br2, heat
O3
Zn, H2O
KMnO4, heat
O=CHCH2CH2CH2CH2CH=O
HO2CCH2CH2CH2CH2CO2H
Epoxides
nomenclature
syntheses
1. epoxidation of alkenes
reactions
1. addition of acids
2. addition of bases
Epoxides, nomenclature
H2C CH2
O
H
H2C C CH3
O
ethylene oxide
propylene oxide
(oxirane)
(methyloxirane)
O
cyclopentene oxide
Synthesis:
C6H5CO3H
O
cis-2-butene
β-butylene oxide
epoxides, reactions:
1) acid catalyzed addition
H2C CH2
O
H2C CH2
O
H2C CH2
O
H2O, H+
CH3CH2OH, H+
HBr
OH
CH2CH2
OH
OH
CH3CH2-O-CH2CH2
OH
CH2CH2
Br
2. Base catalyzed addition
H2C CH2
O
OH
CH2CH2
OH
NaOH, H2O
H2C CH2 NaOCH2CH3
O
CH3CH2OH
H2C CH2
O
H2C CH2
O
NH3
CH3CH2-O-CH2CH2-OH
H2N-CH2CH2-OH
1. CH3CH2MgBr
2. H2O
CH3CH2CH2CH2-OH
Mechanisms:
Free radical substitution
SN2
SN1
E2
E1
ionic electrophilic addition
free radical electrophilic addition
Memorize (all steps, curved arrow formalism, RDS) and know which
reactions go by these mechanisms!
Free Radical Substitution Mechanism
initiating step:
1) X—X  2 X•
propagating steps:
2) X• + R—H
 H—X + R•
3) R• + X—X  R—X + X•
2), 3), 2), 3)…
terminating steps:
4) 2 X•  X—X
5) R• + X•  R—X
6) 2 R•  R—R
Substitution, nucleophilic, bimolecular (SN2)
SN2
RDS
Z:
+
CH3 > 1o > 2o > 3o
C W
Z C
+
:W
Substitution, nucleophilic, unimolecular (SN1)
1)
RDS
C W
C
+
:W
carbocation
2)
C
+
3o > 2o > 1o > CH3
:Z
C Z
Mechanism = elimination, bimolecular E2
W
RDS
C
C
H
base:
3o > 2o > 1o
C
C
+ H:base + :W
Elimination, unimolecular
1)
2)
C C
H W
C C
H
3o > 2 o > 1 o
RDS
-H
E1
C C
H
C C
+ :W
Ionic electrophilic addition mechanism
1)
2)
C C
C C
Y
+
YZ
+ Z
RDS
C C
Y
C C
Z Y
+ Z
Free radical electrophilic addition of HBr:
Initiating steps:
1) peroxide  2 radical•
2) radical• + HBr  radical:H + Br• (Br• electrophile)
Propagating steps:
3) Br• + CH3CH=CH2  CH3CHCH2-Br (2o free radical)
•
4) CH3CHCH2-Br + HBr  CH3CH2CH2-Br + Br•
•
3), 4), 3), 4)…
Terminating steps:
5) Br• + Br•  Br2
Etc.