Final Answer:
Oxymercuration-demercuration is a chemical reaction used to add an alcohol group (-OH) to an alkene in a Markovnikov-selective manner. This process involves two steps: the addition of a mercuric acetate compound followed by its replacement with a reducing agent like sodium borohydride, resulting in the formation of the alcohol.
Step-by-step explanation:
Oxymercuration-demercuration is a method utilized to convert alkenes into alcohols with Markovnikov selectivity. In the first step, an alkene reacts with mercuric acetate (Hg(OAc)2) in the presence of a solvent like water. The π electrons of the double bond attack the mercuric acetate, leading to the formation of a three-membered cyclic mercurinium ion intermediate. This intermediate is unstable and quickly undergoes rearrangement, forming a carbocation on the more substituted carbon due to the Markovnikov rule, resulting in the addition of an acetoxymercury (Hg(OAc)) group to the alkene.
In the second step, the demercuration process takes place using a reducing agent such as sodium borohydride (NaBH4). This step is crucial to replace the mercury (Hg) with a hydrogen atom. Sodium borohydride functions as a nucleophile, attacking the electrophilic acetoxymercury group, resulting in the substitution of the mercury with a hydrogen atom. As a result, the final product is an alcohol compound. This process offers a convenient and efficient means to add alcohol functional groups to alkenes in a regioselective manner, following the Markovnikov rule.