Iniciar sesión

Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can beforced undercertain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of whichis equally susceptible to nucleophilic attack. This 50–50 distribution of products is confirmed through isotopic labeling. The overall mechanism follows an elimination–addition pathway. A strong base generates a carbanionic center on the ring. Next, elimination of the halide produces the benzyne intermediate, which ishighly strainedand therefore extremely reactive at both ends of the triple bond. Addition of the nucleophile at either end gives the product with 50–50 distribution.

Tags

Nucleophilic Aromatic SubstitutionElimination additionAryl HalidesBenzyne IntermediateNucleophilic AttackIsotopic LabelingCarbanionic CenterHalide EliminationStrained IntermediateReactivity

Del capítulo 18:

article

Now Playing

18.19 : Nucleophilic Aromatic Substitution: Elimination–Addition

Reactions of Aromatic Compounds

3.9K Vistas

article

18.1 : Espectroscopía de RMN de derivados del benceno

Reactions of Aromatic Compounds

7.2K Vistas

article

18.2 : Reacciones en la posición bencílica: oxidación y reducción

Reactions of Aromatic Compounds

3.2K Vistas

article

18.3 : Reacciones en la posición bencílica: halogenación

Reactions of Aromatic Compounds

2.3K Vistas

article

18.4 : Sustitución aromática electrofílica: descripción general

Reactions of Aromatic Compounds

10.0K Vistas

article

18.5 : Sustitución aromática electrofílica: cloración y bromación del benceno

Reactions of Aromatic Compounds

7.0K Vistas

article

18.6 : Sustitución aromática electrofílica: fluoración y yodación del benceno

Reactions of Aromatic Compounds

5.5K Vistas

article

18.7 : Sustitución aromática electrofílica: nitración del benceno

Reactions of Aromatic Compounds

5.2K Vistas

article

18.8 : Sustitución aromática electrofílica: sulfonación del benceno

Reactions of Aromatic Compounds

5.1K Vistas

article

18.9 : Sustitución aromática electrofílica: Friedel-Crafts alquilación de benceno

Reactions of Aromatic Compounds

6.1K Vistas

article

18.10 : Sustitución aromática electrofílica: acilación de benceno de Friedel-Crafts

Reactions of Aromatic Compounds

6.4K Vistas

article

18.11 : Limitaciones de las reacciones de Friedel-Crafts

Reactions of Aromatic Compounds

5.1K Vistas

article

18.12 : Efecto Directivo de los Sustituyentes: Grupos Orto-Para-Directores

Reactions of Aromatic Compounds

5.8K Vistas

article

18.13 : Efecto Directivo de los Sustituyentes: Grupos Meta-Directores

Reactions of Aromatic Compounds

4.1K Vistas

article

18.14 : Activadores orto-para-direccionamientos: –CH3, –OH, –⁠NH2, –OCH3

Reactions of Aromatic Compounds

5.4K Vistas

See More

JoVE Logo

Privacidad

Condiciones de uso

Políticas

Investigación

Educación

ACERCA DE JoVE

Copyright © 2025 MyJoVE Corporation. Todos los derechos reservados