The major product of the following reaction is \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}=\mathrm{CHCH}_{3} \frac{\text { (i) } \mathrm{Hg}(\mathrm{OAc})_{2} \mathrm{THF}=\mathrm{H}_{2} \mathrm{O}}{\text { (ii) } \mathrm{NaBH}_{4}}\)

Markovnikov's rule is a fundamental principle in organic chemistry that predicts the outcome of certain chemical reactions, such as the addition of acids to alkenes. Named after Russian chemist Vladimir Markovnikov, the rule states that when a protic acid is added to an unsaturated hydrocarbon like an alkene, the hydrogen (H) from the acid will attach to the carbon with the greater number of hydrogen atoms, and the more electronegative part (such as an OH group) will attach to the carbon with more alkyl substituents. This results in the formation of the most stable carbocation intermediate.

Understanding this concept is crucial when predicting the major product of reactions like oxymercuration-demercuration. Markovnikov's rule helps us determine which carbon on the alkene will be bonded to the hydroxyl (OH) group. In our exercise, the rule implies that the major product will have the OH group attached to the more substituted carbon atom, leading to the formation of a Markovnikov alcohol. This rule highlights the stability imparted by alkyl groups during the intermediate stage of the reaction.

The transformation of alkenes into alcohols involves adding an OH group across the unsaturated carbon-carbon double bond. Such conversions are essential in synthetic organic chemistry since alcohols serve as versatile intermediates for a plethora of other chemical compounds.

In the oxymercuration-demercuration process, an alkene is first converted to an organomercury intermediate which is then reduced to an alcohol. This method is particularly useful as it avoids the formation of carbocations, which can lead to rearrangement and unwanted by-products. Unlike direct hydration that typically follows Markovnikov's rule, oxymercuration-demercuration provides a way to add water across the double bond without carbocation rearrangement, thus offering excellent control over the product distribution. By understanding this pathway, chemists can design syntheses to yield a specific alcohol from a given alkene with high precision.

Organic chemistry revolves around studying carbon-containing compounds and the reactions they undergo. Reactions involving alkenes like the one discussed in our exercise are common and especially significant in the synthesis of various complex molecules.

There are many types of organic reactions, each with unique characteristics and outcomes. Oxymercuration-demercuration is an example of an electrophilic addition reaction, where an electrophile (Hg(OAc)2) selectively adds to the more substituted carbon of the alkene due to Markovnikov's rule. Understanding the mechanistic aspects of such reactions allows chemists to manipulate and control the transformation of simple starting materials into more complex and functional products.

By grasping the rules and patterns of reactivity, like the regioselectivity seen in Markovnikov's rule or the anti-Markovnikov behavior of other additions, students can predict and rationalize the outcome of organic reactions, paving the way for more advanced studies in chemical synthesis and the development of new therapeutic agents, materials, and other chemical products.