Reactions of Alkenes

Question 1

Hydrohalogenation of Alkenes

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 1

Reactants: An alkene and hydrogen halide
Catalysts/Conditions: None
Products: A haloalkane
Intermediate: A carbocation
Regioselectivity: Mark
Stereoselectivity: None

Question 2

Acid-Catalyzed Hydration of Alkenes

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 2

Reactants: An alkene and H2O
Catalysts/Conditions: Acid Catalyst (H2SO4, HCl, etc)
Products: An alcohol
Intermediate: A carbocation
Regioselectivity: Mark
Stereoselectivity: None

Question 3

Acid-Catalyzed Ether Synthesis

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 3

Reactants: An alkene and an alcohol
Catalysts/Conditions: Acid Catalyst (H2SO4, HCl, etc)
Products: An ether
Intermediate: A carbocation
Regioselectivity: Mark
Stereoselectivity: None

Question 4

Halogenation of Alkenes

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 4

Reactants: Alkene and X2
Catalysts/Conditions: CH2Cl2 aka DCM (inert solvent)
Products: X2 added anti addition
Intermediate: Cyclic bridge (no carbocation)
Regioselectivity: Mark
Stereoselectivity: Anti Addition

Question 5

Halohydrin Synthesis 
(Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity)

Answer 5

Reactants: Alkene, X2 and H2O
Catalysts/Conditions: None
Products: X and OH added 
Intermediate: Cyclic bridge w X
Regioselectivity: OH Mark
Stereoselectivity: Anti addition

Question 6

Oxymercuration-Demercuration of Alkenes

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 6

Reactants: 1. Alkene and Hg(OAc)2, THF, H2O
2. NaBH4, H2O
Catalysts/Conditions: None
Products: Alcohol
Intermediate: 1. Cyclic Bridge w HgOAc
Regioselectivity: OH Mark
Stereoselectivity:

Question 7

Hydroboration Oxidation of Alkenes

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 7

Reactants: 1. Alkene, BH3, and THF 2. H2O2 and NaOH
Catalysts/Conditions: none
Products: Alcohol
Intermediate: No carbocation, H/BH2 added at same time
Regioselectivity: OH Anti Mark
Stereoselectivity: Syn addition

Question 8

Dihydroxylation of Alkenes

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 8

Reactants: 1. Alkene and OsO4 2. H2O2 and H2O
Catalysts/Conditions: None
Products: Diol
Intermediate: 1. cyclic osmate intermediate
Regioselectivity: None
Stereoselectivity: Syn Addition

Question 9

Ozonolysis of Alkenes

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 9

Reactants: 1. Alkene and O3 2. Dimethyl Sulfide (DMS)
Catalysts/Conditions: None
Products: Aldehyde/Ketone
Intermediate: None
Regioselectivity: None
Stereoselectivity: None

Question 10

Catalytic Reduction of Alkenes

Reactants (including conditions/catalysts), Products, Intermediates, Regioselectivity, Stereoselectivity

Answer 10

Reactants: Alkene, H2 
Catalysts/Conditions: Pt or Pd or Ni Catalyst
Products: Alkane
Intermediate: None
Regioselectivity: None
Stereoselectivity: H/H Syn Addition

Question 11

Can we rotate about C=C bond?

Answer 11

No, will break pi bond.

Question 12

Which step is the rate-determining step?

Answer 12

The one that crosses the highest energy barrier.

Question 13

What factors control carbocation stability and in what way?

Answer 13

1. Hyperconjugation - stabilizes
2. Resonance - stabilizes
3. Inductive effect - destabilizes

Question 14

What are the alkene reactions that create alcohols?

Answer 14

Acid-Catalyzed Hydration of Alkenes
Oxymercuration-demercuration
Hydroboration-Oxidation of Alkenes
Dihydroxylation of Alkenes (Diol)