In which of the following addition reactions is a carbocation rearrangement poss
ID: 909298 • Letter: I
Question
In which of the following addition reactions is a carbocation rearrangement possible? Check all that apply.
Select one or more:
a. Oxymercuration-demercuration
b. Halogenation
c. Dihydroxylation
d. Hydrohalogenation
e. Hydrogenation
f. Hydroboration-oxidation
g. Acid-catalyzed hydration
Which of the following reactions gives exclusively syn addition? Check all that apply.
Select one or more:
a. Reaction with HBr
b. Hydroboration-oxidation
c. Acid-catalyzed addition of water
d. Oxymercuration-demercuration
e. Formation of a chlorohydrin with Cl2 and water
f. Dihydroxylation with osmium tetroxide
g. Bromination
h. Hydrogenation with a Pt catalyst
Peroxide-mediated addition of H-X across a double bond with anti-Markovnikov regiochemistry works best with which hydrogen halide?
Select one:
a. HCl
b. HI
c. HBr
d. HF
Explanation / Answer
1) in case of hydrohalogenation possibility of carbocation rearrangement. because in first step there will be carbocation intermediate so it can re arrange if possible.
2)
h. Hydrogenation with a Pt catalyst . catalytic hydrogenation is concerted mechanism so only syn addition possible.
3) c. HBr
HBr bond strebgth suitable for free radical generation. because in peroxide medium free radical addition takes place.