Alkenes and Alkynes 2

Question 1

Addition of HX (hydrohalogenation)

Answer 1

1. grab proton and form carbocation
2. X- added to carbocation
   follow Markonikov’s Rule

Question 2

Hydration

Answer 2

1. grab proton and form carbocation
2. deprotonation
   follow Markovnikov’s Rule
   Acid Catalyst (H2SO4)

Question 3

Halogenation

Answer 3

1. Forming bridge with X+ ion
2. X- backside attack
   anti-addition

Question 4

Hydroboration-oxidation

Answer 4

hydroboration: BH3,
anti-Markovnikov’s Rule
oxidation: H2O2, OH-
syn-addition

Question 5

Dihydroxylation of alkenes

Answer 5

OsO4, py NaHSO3/H2O
syn-addition

Question 6

Halohydrin formation

Answer 6

1. X2, H2O
   forming alcohol, haloalkane and HX
   anti-addition

Question 7

Addition of X2 to alkynes

Answer 7

follow markovnikov’s rule

Question 8

Alkyne to Alkane

Answer 8

Pt, H2

Question 9

Alkyne to (E)-alkene

Answer 9

H2, Lindlar’s catalyst
syn-addition