Markovnikova
Markovnikova refers to a set of rules in organic chemistry that predict the regiochemistry of electrophilic addition reactions to unsymmetrical alkenes and alkynes. Specifically, it describes how a hydrogen atom and a halogen atom (or another group) add across a double or triple bond. The original formulation, developed by Vladimir Markovnikov in 1870, states that in the addition of a protic acid HX to an alkene, the hydrogen atom adds to the carbon atom that already has the greater number of hydrogen atoms attached. Consequently, the halide (X) adds to the more substituted carbon atom.
This rule is a consequence of the stability of the carbocation intermediate formed during the reaction. In
While Markovnikov's rule is a powerful predictive tool, it has limitations and exceptions. For instance, in