Reaction Reagents, Solvents and Catalysts

Question 1

Hydrohalogenation

Answer 1

Reactant: Alkene + HX
Carbocation Intermediate
Product: Markovnikov alkyl halide

Reactant: alkyne + 1 equivalent HX
Carbocation Intermediate
Product: E/Z mix halide alkene

Reactant: alkyne + xs HX
Carbocation Intermediate
Product: geminal dihalide alkane

Question 2

Free Radical Hydrohalogenation

Answer 2

Reactants: Alkene + HX
Catalyst: ROOR
Product: Anti-markovnikov alkyl halide

Reactants: Alkyne + 1 eq HX
Catalyst: ROOR
Product: Anti-markovnikov alkene halide E/Z mix

Question 3

Acid-catalyzed hydration

Answer 3

Reactants: Alkene + dilute Acid (H3O+ or H2SO4)
Catalyst: water
Carbocation Intermediate
Product: markovnikov hydroxyl (OH)

Reactant: alkyne + H2SO4 + H2O + HgSO4
Catalyst: water
Intermediate: Enol
Product: Ketone

Question 4

Hydroboration

Answer 4

Reactants: Alkene + BH3, THF/H2O2, NaOH
Products: anti-markovnikov hydroxyl (OH), syn addition of OH and H

Reactants: Alkyne + BH3, THF/H2O2, NaOH
Intermediate: anti-markovnikov enol
Products: anti-markovnikov aldehyde

Reactant: Alkyne + R2BH (disamylborane), H2O2, NaOH
intermediate: anti-markovnikov Enol
Product: anti-markovnikov aldehyde

Question 5

Hydrogenation

Answer 5

Reactants Alkene: Alkene + H2
Catalyst: Pt/Pd
Products: Alkane - full saturated, syn addition of Hs

Reactants alkyne: alkyne + H2
Catalyst: Lindlar’s catalyst (poisoned catalyst)
Product: cis alkene

Reactant alkyne: alkyne + H2
Catalyst: Na (s) + NH2 (l)
Product: trans alkene

Reactant alkyne: alkyne + xs H2
Catalyst: Pt/Pd
Product: alkane, fully saturated

Question 6

Halogenation

Answer 6

Reactants Alkene: alkene + X2
Intermediate: Br tent
Products: disubstituted alkyl halide, anti addition of Xs

Reactant alkyne: alkyne + 1 equivalence X2
Products: disubstituted trans alkene halide (major) and disubstituted cis alkene halide (minor)

Reactant alkyne: alkyne + xs X2
Products: tetra-substituted alkyl halide

Question 7

Halohydrin Formation

Answer 7

Reactant: alkene + Br2
Catalyst: H2O
Intermediate: Br tent
Product: hydroxyl-bromo alkane, markovnikov addition of OH, anti to Br

Question 8

Oxidative Cleavage

Answer 8

Reactant: alkene + O3 + DMS
Product: splits pi bond in half, into ketones/aldehydes depending

Reactant: internal alkyne + O3 + H2O
Product: splits pi bonds in half, into 2 carboxylic groups

Reactant: terminal alkyne + O3 + H2O
Product: splits pi bonds in half, into 1 carboxylic group + CO2

Question 9

Alkylation of Alkynes

Answer 9

Reactant: 1) terminal alkyne + NaNH2 2) alkyl halide
Product: alkylated alkyne
(can be done twice on acetylene)