CJMM | 1

REACTIONS OF HYDROCARBONS

REACTIONS OF ALKANES

1. Combustion

OHnnCOOHC nnn 2222

1322 )1(

2. Free Radical Halogenation

CH X2

heat

light CX + H - X+

Where X2 = Cl2, Br2

3. Pyrolysis

REACTIONS OF CYLOALKANES

1. Combustion

OnHnCOOHC nnn 2222

32

2. Ring Opening Reactions

Cyclopropane

Cl2, light

RT

Cl2, FeCl3

HX

H2, Ni at 800C

Cl

ClCl

XH

HH

* Dashed lines are bonds that are broken

CJMM | 2

REACTIONS OF ALKENES

A. Electrophilic Addition

General Addition Reaction:

C C + X - Yreaction

conditions

YX

1. Hydrogenation

C C + Ni ,Pd

or Pt

HH

+H2

* Syn – Addition

2. Addition of HX

C C +

XH

HX

where HX = HCl, HBr or HI * Addition of HX follows Markovnikov’s Rule

3. Addition of Water or Hydration

C C +

OHH

H2OH+

alcohol * Addition of Water also follows Markovnikov’s Rule

4. Addition of cold concentrated H2SO4

C C +

OSO3HH

H2SO4

5. Addition of Halogen

C C +

X

X

X2

where X2 = Cl2 or Br2

CCl4 / CH2Cl2

* Anti-addition (Due to cyclic halonium ion that has a high steric hindrance)

CJMM | 3

6. Halohydrin Formation

C C +

OH

X

X2, H2O

where X2 = Cl2 or Br2

+ HX

* Anti-addition (Due to cyclic halonium ion that has a high steric hindrance)

7. Addition of Alkenes: Dimerization

2

isooctane

800

8. Addition of Alkenes: Alkylation

C C +con'c H2SO4/ HF

0 -10 0C

HR

R - H

+

H3C

HC

CH3

CH3

con'c H2SO4/HF

0- 10 0C

H3C

C

C

C

CH3

CH3

CH3

CH3

H

H H

9. Oxymercuration – Demercuration

RCH = CH2

1. H2O, Hg(OAC)2

2. NaBH4

RCH CH2

OH

H

* Markovnikov Orientation

* Anti – addition

CJMM | 4

10. Hydroboration – Oxidation

RCH = CH2

1. BH3, THF

2. H2O2, -OHRCH CH2

H

OH

* Reverse Markovnikov Orientation

* Syn – addition

11. Alkoxymercuration – Demercuration

C C +

ORH

ROH1. Hg(O2CCF3)2

2. NaBH4

ether * Note: Hg(OAc)2 can be used.

* Produces an ether from an alcohol/ alkoxy group.

12. Hydroxylation or Glycol Formation

C C +

OHHO

KMnO4

cis - 1,2- diol

+ MnO2

* Syn – addition

* occurs with H2O

Alternative Reaction:

C C

OHHOcis - 1,2- diol

1. OsO4, pyridine

2. NaHSO3, H2O

* Produces the same product as cold dilute neutral KMnO4

13. Oxidative Cleavage: Ozonolysis

C C C O1. O3

2. Zn, H30+

2

CJMM | 5

14. Oxidative Cleavage: Hot acidic KMnO4

C C

R

H H

R

C O

R

HO

hot acidic KMnO42

C C

R

R H

H

C O

R

R

hot acidic KMnO4 + CO2

Notes:

CH2 CO2

C

H

O C

OH

CO C

15. Epoxidation

C C +

C C

epoxide

C

O

O

OH

MCPBA

m- chloroperoxybenzoic acid

OR

C

OH

O

+

* Instead of MCPBA, RCO3H is used as reagent where R is an alkyl group

CJMM | 6

16. Carbenes

Generation of carbene

CHCl3chloroform

+ KOH

Cl

C

Cl

Cl

+ H2O

trichloromethanide

C C + CHCl3KOH

C

Cl Cl

Note: Stereochemistry is retained. A cis-alkene will result to a cis-

disubstituted cyclopropane.

17. Simmons – Smiths Reaction, Carbenoid

CH2I2 + Zn(Cu)ether

I - CH2 - Zn - I = ":CH2"

Example:

+ CH2I2

ether

Zn(Cu)CH2

H

H

+ ZnI2

18. Addition of HBr with ROOR, known as Peroxide effect

H3C

C

CH2

CH3

+ HBrROOR

H3C

CH

CH2Br

CH3

* Note: not applicable for other Acid Halides such as HCl

* Reverse Markovnikov Orientation

* Free Radical Addition

CJMM | 7

REACTIONS OF POLYMERS

1. Free Radical Polymerization

n CH2 = CH2O2, 100 - 250 0C

1000 - 300 atm

or peroxides

CH2CH2 n

2. Allylic Halogenation or Wohl-Ziegler Bromination

C

C

C

H

N

O

O

Br

NBS

ROOR, CCl4

C

C

C

Br

H+

* uses NBS, n-bromosuccinimide

* Br is attached to an allylic carbon

* Possible rearrangement can occur due to allylic carbon

REACTIONS OF DIENES OR ALKADIENES

1. Electrophilic Addition of Dienes

H2C

HC

CH

HC

CH2

H

X - Y

CH2

CH

CH

HC

CH2

H

X

Y

CH2

CH

CH

CH

CH2

H

X

Y X

Y

X - Y

* Reacts like normal alkenes

CJMM | 8

H2C

C

C

CH2

X - Y

X - Y

H

H

H2C

C

C

CH2

H

H

H2C

C

C

CH2

H

H

X

Y

X

Y

1,2 addition product

1,4 addition product 2. Diels – Alder Cycloaddition Reaction

+benzene,

3. Free Radical Polymerization of Dienes

n (CH2 = CH - CH = CH2) ( CH2 - CH = CH - CH2 )n * Results in a 1, 4- addition

NOTES:

Stability of Free Radicals:

Allylic, Benzyllic > 3o > 2 o > 1 o > •CH3 > Vinyl

Stability of Carbocations: Subsituted Allylic and Benzyllic > 3o > Allylic, Benzyllic > 2 o > 1 o > Vinyl > CH3

+

CJMM | 9

REACTIONS OF ALKYNES

1. Hydrogenation

C C2H2

Ni, Pt or Pd C C

H

H H

H

C CNa or Li

liquid NH3 C C

H

H * Trans- alkene, Anti – addition

C CLindlar Catalyst C C

H H

H2

* Cis – alkene, Syn – addition

2. Electrophilic Addition

C CC C

X

X X

X

2X2

CCl4

C CC C

Br

Br H

H

2HBr

3. Hydration

C C C C

H

OH

+ H2OH2SO4

HgSO4

enol

C C

H

H O

ketone

Over-all Reaction:

R C C H + H2OH2SO4

HgSO4C C

H

H O

CH3

R

* Follows a Markovnikov orientation

CJMM | 10

4. Hydroboration – Oxidation of Terminal Alkynes

R C C H C C

H

R H

OH

1. B2H6

2. NaOH, H2O2

enol

C C

H

H O

H

R

ketone

* Follows a reverse Markovnikov orientation

5. Acidity of Terminal Alkynes Na

NaNH2

alcoholic AgNO3

R C C Na

R C C Na + NH3

R C C Ag

R C C H

6. Ozonolysis

a. Internal Alkyne

R C C R'1. O3

2. Zn, H3O+ R C OH

O

+

R' C OH

O

b. Terminal Alkyne

R C C H1. O3

2. Zn, H3O+ R C OH

O

+ O C O

7. Alkylation of Acetylide Anions

RCH2 - X + R C CSN2

H2C C C RR

CJMM | 11

REACTIONS OF ALKYL HALIDES

1. SN1, Unimolecular Nucleophilic Substitution

1.

C

R

R

R X

slowC

R

R

R+ X

2.

C

R

R

RNu

fast

C

R

R

R Nu

2. SN2, Bimolecular Nucleophilic Substitution

Nu XCslow

CNu X

Transition State

fast

CNu

+ X

3. E1, Unimolecular Elimination Reaction

C C

H

X

Base

slow C C

X

HB

fastC C +HB + X

4. E2, Bimolecular Elimination Reaction

1.

C

R

R

R X

slowC

R

R

R+ X

2.

C

H

C

Base

fastC C

R

R

+ BH

CJMM | 12

REACTIONS WITH ORGANOMETALLIC COMPOUNDS

1. Grignard Reagents

2. Organometallic Coupling Reactions

a. Alkyllithium Reagent

CH3CH2CH2CH2Br2Li

pentaneCH3CH2CH2CH2Li + LiBr

b. Gilman Reagent

3CH3Li + CuI ether(CH3)2Cu-Li+ + LiI

c. Organometallic Coupling

(CH3)2CuLi + CH3(CH2)2CH2I CH3(CH2)2CH2CH3 + LiI + CH3Cu

Example: I

+ (CH3)2CuLi

CH3

+ CH3Cu + LiI

REACTIONS WITH AROMATIC HYDROCARBONS

Electrophilic Aromatic Substitution (EAS)

1. Nitration

H

+ HNO3

NO2

+ H2OH2SO4

nitrobenzene

R

CX + Mg

dry ether

R

CMg X or Ar - MgX

CJMM | 13

2. Halogenation

H

+ X2

X

+ HXFe or FeX3

halobenzenewhere X2 = Cl2 or Br2

3. Sulfonation

H

+ SO3

SO3H

+ H2Ofuming H2SO4

benzenesulfonic acid

4. Friedel-Crafts Alklyation

H

+ R - Cl

R

+ HClAlCl3

alkylbenzene

alkyl chloride

5. Friedel-Crafts Acylation

HC

+ HClAlCl3

aromatic ketone

+ C

O

R

Cl

acid chloride

O

R

6. Oxidation of Alkyl Side Chains

R COOH

hot acidic KMnO4

where R contains a benzylic hydrogen

CJMM | 14

Nucleophilic Aromatic Substitution (NAS)

1. Bimolecular Displacement or Addition – Elimination, SNAr

X

+ Z:

Z

+ X:

Mechanism:

1.

X

+ Z:slow

X Z X Z X Z

Meisenheimer Complex

2.

X ZZ

+ X:

CJMM | 15

2. Elimination – Addition or Benzyne Mechanism

X NH2

- NH2

NH3

Mechanism

X

H

NH2

X

+ NH3

X

+ X

benzyne

1.

2.

3.

NH2NH2

4.

NH2

H NH2

NH2

+ NH2