Quiz - Reactions of Alkenes - 3 | Reactions of Alkenes

Organic Chemistry 2 - Quiz - Reactions of Alkenes - 3


Which of the following best describes the mechanism of the hydroboration-oxidation of alkenes?

The hydroboration occurs through a concerted mechanism involving syn addition, while the oxidation step converts the boron-substituted intermediates into alcohols.


How does the reactivity of alkenes towards halogenation compare with alkanes, and why?

Alkenes are more reactive towards halogenation compared to alkanes due to the higher electron density associated with their π-bonds, making them more attractive to electrophiles such as halogens.


What is the result of ozonolysis of cyclohexene?

Ozonolysis of cyclohexene cleaves the double bond, resulting in the opening of the ring and the formation of 2 aldehydes on either side of the six-carbon chain. 


What is the consequence of syn dihydroxylation on cyclic alkenes in terms of product formation?

In syn dihydroxylation, both hydroxyl groups are added to the same face of the alkene, leading to the formation of cis diols. This is particularly evident in cyclic alkenes.


Which product is expected when but-1-ene undergoes hydrohalogenation following Markovnikov's rule?

According to Markovnikov's rule, the halogen will add to the more substituted carbon of the alkene, and if this carbon is stereogenic, it will result in the formation of both enantiomers.


What role does the metal catalyst play in the hydrogenation of alkenes?

A metal catalyst like Pt, Pd, or Ni adsorbs the alkene and hydrogen, facilitating their interaction and leading to the addition of hydrogen across the double bond.


What distinguishes the reaction conditions between hydration of alkenes using acid-catalyzed hydration vs. oxymercuration-demercuration?

Acid-catalyzed hydration involves a carbocation intermediate that can rearrange, whereas oxymercuration-demercuration proceeds through a mercurinium ion intermediate that typically prevents carbocation rearrangements, leading to more regioselective outcomes.


Why is the radical bromination of alkenes selective for the allylic position?

Radical bromination is selective for the allylic position because the resonance stabilization of the allylic radical intermediate lowers the energy barrier for bromine radical addition at this position, making it more favorable than addition directly to the double bond.