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🥼organic chemistry review

Electrophilic

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Electrophilic refers to a species or reagent that is attracted to or seeks out electron-rich regions, typically in organic chemistry reactions. These species are often positively charged or have a partial positive charge, and they interact with and form bonds with nucleophiles, which are electron-rich species.

5 Must Know Facts For Your Next Test

  1. Electrophiles are often positively charged species or have a partial positive charge, which allows them to interact with and form bonds with nucleophiles.
  2. Electrophilic species are attracted to electron-rich regions, such as the π-electrons of carbon-carbon double bonds or the lone pairs of heteroatoms like oxygen and nitrogen.
  3. Electrophilic addition reactions involve the addition of an electrophile to a carbon-carbon double bond, forming a new product.
  4. Electrophilic aromatic substitution reactions involve the replacement of a hydrogen atom on an aromatic ring with an electrophilic species, forming a new product.
  5. The concept of electrophilicity is crucial in understanding the reactivity and mechanism of many organic chemistry reactions, including nucleophilic addition reactions of aldehydes and ketones, hydration reactions, and the Wolff-Kishner reduction.

Review Questions

  • Explain how the electrophilic nature of a species affects its reactivity in organic chemistry reactions.
    • The electrophilic nature of a species determines its ability to interact with and form bonds with nucleophiles, which are electron-rich species. Electrophiles, being attracted to electron-rich regions, can participate in various organic reactions, such as electrophilic addition to carbon-carbon double bonds and electrophilic aromatic substitution. The electrophilicity of a species is a key factor in understanding the reactivity and mechanism of many organic chemistry reactions, including those involving aldehydes, ketones, and the Wolff-Kishner reduction.
  • Describe the role of electrophilicity in the nucleophilic addition reactions of aldehydes and ketones.
    • In the nucleophilic addition reactions of aldehydes and ketones, the carbonyl carbon acts as an electrophilic site, attracting nucleophiles to form new products. The electrophilic nature of the carbonyl carbon is due to the partial positive charge on the carbon, which is a result of the electronegativity difference between carbon and oxygen. This electrophilicity allows the carbonyl carbon to be attacked by nucleophiles, such as water, hydride, and Grignard reagents, leading to the formation of alcohols and other products.
  • Analyze how the concept of electrophilicity is relevant in the Wolff-Kishner reduction reaction.
    • In the Wolff-Kishner reduction, the carbonyl carbon of an aldehyde or ketone is first attacked by the nucleophilic hydrazine, forming an intermediate imine. The imine then undergoes a rearrangement, where the electrophilic carbon-nitrogen bond is cleaved, and the nitrogen is eliminated as ammonia. The remaining carbon-carbon bond is then reduced, forming the final alkane product. The electrophilic nature of the carbonyl carbon and the imine intermediate are crucial in facilitating the sequence of steps in this reaction, demonstrating the importance of understanding electrophilicity in organic chemistry mechanisms.