Alkyne Reactions

Question 1

Hydrogen Halogenation

Answer 1

Regiochemistry: Markovnikov

Reactants: Alkyne

Reagents: HX (HBr) or excess HX

Products: normal: alkene with a halogen attached, excess: alkane with one carbon with 2 halogens

Question 2

Halogenation

Answer 2

Reactant: Alkyne

Reagents: X_2, Cl₂ and CH₂Cl₂

Products: normal: alkene with a halogen attached to both carbons attached to the double bond, excess: alkane with 2 halogens attached to both carbons attached to the double bond

Question 3

Acid Catalyzed Addition of Water

Answer 3

Reactant: Internal Alkyne

Reagents: H₂O and H₂SO₄

Reactant: Terminal Alkyne

Reagents: H₂0 and H₂SO₄

Product: Ketone

Question 4

Hydroboration Oxidation

Answer 4

Reactant: Internal Alkyne

Reagents:
1.BH3/THF

2. H₂O₂, OH, H₂O

Product: Ketone

Reactant: Terminal Alkyne

Reagents: the same

Product: Aldehyde

Question 5

Formation of an Alkane

Answer 5

Reactant: Alkyne

Reagents: 2H₂ amd Pd/C

Product: Alkane

Question 6

Formation of a Cis Alkene

Answer 6

Reactant: Alkyne

Reagents: H₂ in Lindler’s Catalyst

Product: Cis Alkene

Stereochemistry: Syn

Question 7

Formation of a Trans Alkene

Answer 7

Reactant: Alkyne

Reagents: Na or Li, -78ºC and NH₃(liquid)

Product: Trans Alkene

Stereochemistry: Anti