Alkene Addition Reactions

Question 1

HX
——>

Answer 1

Hydrohalogenation

• Halogen is added to more substituted Carbon on the double bond

Question 2

HBr
———>

ROOR

Answer 2

Radical Addition

• Anti Markovnikov addition of H and Br
• Occurs in presence of Peroxide ROOR

Question 3

H20
—————>
Catalytic Acid

Answer 3

Acid Catalyzed Hydration

• Markovnikov addition of H and OH
• Converts Alkene to an Alcohol
• Carbocation Rearrangements are possible

Question 4

1) Hg(OAc)2, H2O, THF
———————————>
2) NaBH4

Answer 4

Oxymercuration - Demercuration

• Markovnikov addition of H and OH
• if 1 chiral center is formed, then there are 2 products
• if 2 chiral centers are formed, then there are 4 products
• NO CARBOCATION REARRANGEMENTS

Question 5

1) BH3, THF
——————>
2) H2O2, NaOH

Answer 5

Hydroboration Oxidation

• Anti Markovnikov addition of H and OH
• Stereospecific SYN addition
• No Carbocation Rearrangements

Question 6

Br2 or Cl2
—————>
CCl4

Answer 6

Dihalogenation
- Anti Addition of Br2 or Cl2
- Stereospecific
- Involves formation of Halonium Ion Intermediate
- Practice Mechanism!

Question 7

Br2 or Cl2
—————>
H2O

Answer 7

Halohydrin Formation
- Anti Addition of Br/Cl and an OH group
- Involves formation of Halonium Intermediate, followed by water attacking most substituted ring carbon
- Stereospecific

Question 8

RCO3H
————>
mCPBA

Answer 8

Epoxidation

• Results in an Epoxide
• If product is Chiral, both enantiomers will be formed

Question 9

1) RCO3H, mCPBA
—————————>
2) H3O+

Answer 9

Anti Dihydroxylation

• Anti Addition of two OH
• Alkene is reacted with Peroxyacid such as RCO3H or mCPBA
• the epoxide that forms is reacted with aqueous acid (acid and H2O) or aqueous base (NaOH and H2O)
• Practice Mechanism!

Question 10

1) OsO4 1) KMnO4, NaOH
————> ————————>
2) H2O2 Cold

Answer 10

SYN Dihydroxylation
- the addition of two OH on an Alkene in SYN fashion
- product will include its associated enantiomer

Question 11

Reductive Workup

1) O3
———————————>
2) DMS or Zn, HOAc

Answer 11

Oznolysis Reductive Workup

• cleaves carbon-carbon double bond to produce two carbonyl containing compounds
• if an Alkene carbon is bonded to a hydrogen, a reductive workup converts the Alkene carbon to an ALDEHYDE
• if an Alkene carbon is bonded to two carbon atoms, a keytone is produced regardless of workup used

Question 12

Oxidative Workup

1) O3
————>
2) H2O2

Answer 12

Oznolysis Oxidative Workup

• cleaves carbon-carbon double bond to produce two carbonyl containing compounds
• if an Alkene carbon is bonded to a hydrogen, a oxidative workup converts the Alkene carbon to a carboxylic acid
• if an Alkene carbon is bonded to two carbon atoms, a keytone is produced regardless of workup used

Question 13

H2
—————>
Pd, Pd/C, Pt

Answer 13

Catalytic Hydrogenation

• Reduces an Alkene to an Alkane
• Alkene will react with Hydrogen atoms on surface of a metal catalyst
• Either side of the Alkene can interact with the metal catalyst in a SYN fashion
• Both Enantiomers are formed