Question

• What is the origin of the alpha effect, that is, that nucleophiles with an electronegative atom with lone pairs adjacent to the nucleophilic center are particularly reactive?

Answer 1

The origin of the α-effect, i.e., the enhanced reactivity of nucleophiles that have an unshared pair of electrons on the atom adjacent to the nucleophilic center, relative to a normal nucleophile of the same basicity, has been a source of continuing challenge to investigators since this phenomenon was brought to light

Examples of nucleophiles are anions such as Cl⁻, or a compound with a lone pair of electrons such as NH₃ (ammonia). In the example below, the oxygen of the hydroxide ion donates an electron pair to form a new chemical bond with the carbon at the end of the bromopropane molecule.

Comments

That's not only the origin and not confirmed