Nucleophilic aromatic addition-elimination

Mechanism 17-7 Nucleophilic Aromatic Substitution (Addition-Elimination) 787... [Pg.17]

Nucleophilic Aromatic Substitution Addition-Elimination (Section 22.3B) The... [Pg.983]

NUCLEOPHILIC AROMATIC SUBSTITUTION Addition-Elimination Elimination-Addition... [Pg.1231]

The Addition-Elimination Mechanism of Nucleophilic Aromatic Substitution... [Pg.977]

THE ADDITION-ELIMINATION MECHANISM OF NUCLEOPHILIC AROMATIC SUBSTITUTION... [Pg.977]

The generally accepted mechanism for nucleophilic aromatic substitution m nitro substituted aryl halides illustrated for the reaction of p fluoromtrobenzene with sodium methoxide is outlined m Figure 23 3 It is a two step addition-elimination mechanism, m which addition of the nucleophile to the aryl halide is followed by elimination of the halide leaving group Figure 23 4 shows the structure of the key intermediate The mech anism is consistent with the following experimental observations... [Pg.977]

Although nucleophilic aromatic substitution by the elimination-addition mecha nism IS most commonly seen with very strong amide bases it also occurs with bases such as hydroxide ion at high temperatures A labeling study revealed that hydroly SIS of chlorobenzene proceeds by way of a benzyne intermediate... [Pg.985]

Section 23 6 Nucleophilic aromatic substitutions of the type just shown follow an addition—elimination mechanism... [Pg.987]

Other aryl halides that give stabilized anions can undergo nucleophilic aromatic substitution by the addition-elimination mechanism Two exam pies are hexafluorobenzene and 2 chloropyridme... [Pg.987]

Nucleophilic aromatic substitution can also occur by an elimination-addition mechanism This pathway is followed when the nucleophile is an exceptionally strong base such as amide ion m the form of sodium amide (NaNH2) or potassium amide (KNH2) Benzyne and related arynes are intermediates m nucleophilic aromatic substitutions that pro ceed by the elimination-addition mechanism... [Pg.987]

Nucleophilic aromatic substitution by the elimination-addition mecha nism can lead to substitution on the same carbon that bore the leaving group or on an adjacent carbon... [Pg.987]

The product of this reaction as its sodium salt is called a Meisenheimer complex after the Ger man chemist Jacob Meisenheimer who reported on their formation and reactions in 1902 A Meisenheimer complex corresponds to the product of the nucleophilic addition stage in the addition-elimination mechanism for nucleophilic aromatic substitution... [Pg.991]

The reaction of benzenesulfomc acid with sodium hydroxide (first entry m Table 24 3) proceeds by the addition-elimination mechanism of nucleophilic aromatic substi... [Pg.1000]

Addition-elimination mechanism (Section 23 6) Two stage mechanism for nucleophilic aromatic substitution In the addition stage the nucleophile adds to the carbon that bears... [Pg.1274]

Cycloalkene (Section 5 1) A cyclic hydrocarbon characterized by a double bond between two of the nng carbons Cycloalkyne (Section 9 4) A cyclic hydrocarbon characterized by a tnple bond between two of the nng carbons Cyclohexadienyl anion (Section 23 6) The key intermediate in nucleophilic aromatic substitution by the addition-elimination mechanism It is represented by the general structure shown where Y is the nucleophile and X is the leaving group... [Pg.1280]

Nucleophilic aromatic substitution (Chapter 23) A reaction m which a nucleophile replaces a leaving group as a sub stituent on an aromatic nng Substitution may proceed by an addition-elimination mechanism or an elimination-addition mechanism... [Pg.1289]

Nucleophilic Aromatic Substitution by the Addition-Elimination Mechanism... [Pg.589]

There are several mechanisms by which net nucleophilic aromatic substitution can occur. In this section we will discuss the addition-elimination mechanism and the elimination-addition mechanism. Substitutions via organometallic intermediates and via aryl diazo-nium ions will be considered in Chapter 11 of Part B. [Pg.590]

The addition-elimination mechanism uses one of the vacant n orbitals for bonding interaction with the nucleophile. This permits addition of the nucleophile to the aromatic ring without displacement of any of the existing substituents. If attack occurs at a position occupied by a potential leaving group, net substitution can occur by a second step in which the leaving group is expelled. [Pg.590]

SECTION 10.5. NUCLEOPHILIC AROMATIC SUBSTITUTION BY THE ADDITION ELIMINATION MECHANISM... [Pg.591]

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