Final answer:
The oxymercuration-demercuration sequence on alkenes results in the Markovnikov addition of H2O, preventing skeletal rearrangement, to form alcohols. Option B is correct.
Step-by-step explanation:
The oxymercuration-demercuration sequence is a synthetic route used to convert alkenes to alcohols. When an alkene undergoes oxymercuration followed by demercuration, the synthetic goal achieved is the Markovnikov addition of H2O wherein skeletal rearrangement is prevented.
This process is highly regioselective for the Markovnikov product, meaning that the hydroxyl group (-OH) will attach to the more substituted carbon atom, while an H atom will attach to the less substituted carbon. The mechanism involves the formation of a mercurinium ion intermediate that prevents the skeletal rearrangement that can occur in other types of addition reactions, such as acid-catalyzed hydration of alkenes.
Oxymercuration-demercuration is a two-step process where an alkene reacts with mercuric acetate followed by treatment with sodium borohydride to remove the mercury. This reaction adds water to the alkene in a way that the hydrogen attaches to the less substituted carbon and the oxygen attaches to the more substituted carbon, leading to anti-Markovnikov addition.
This process is useful in organic synthesis as it allows for the addition of water to alkenes without the risk of rearrangements occurring in the carbon skeleton.