Alkyne reactions

Question 1

H2 on Pd/C

Answer 1

Catalytic reduction.
First step: Adds two H atoms with syn addition
Second step: adds two more H atoms across triple bond
Basically gets rid of the triple bond to create an alkane

Question 2

H2 on Lindlar’s catalyst

Answer 2

Converts an alkyne to an alkene with syn addition.

Question 3

Na(s) and NH3(l)

Answer 3

Basically converts an alkyne to a trans alkene.

Question 4

HgSO4, water, and H2SO4

Answer 4

Converts an alkyne to enol then to a ketone

Question 5

Hydrohalogenation

Answer 5

Reagent is HX. Markovnikov, anti-addition of H and X atoms. Converts an alkyne to an alkene with 1 molar eq. and to an alkane with 2 molar eq.

Question 6

Hydroboration-oxidation

Answer 6

Reagents are BH3 or (sia)2BH for the first step and NaOH and H2O2 for the second step. Converts and alkyne to an aldehyde. Anti-markovnikov