Nucleophilic substitution reactions of acid

Acid chlorides are very reactive and can be converted into a variety of compounds, including less reactive carboxylic acid derivatives. 

Under the same conditions, carboxylic acids can undergo acid-base reactions to produce salts. 

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Furthermore, a neighboring group participation of a phenylthio function is observed in the Lewis acid-catalyzed nucleophilic substitution reaction of various P-nitrosulfides. Because the P-nitrosulfides are readily available, by the Michael addition of thiols to nitroalkenes (see Michael addition Chapter 4), this reaction is very useful. The P-nitrosulfides are prepared stereoselectively, and the reaction proceeds in a stereo-specific way (retention of configuration) as shown in Eqs. 31-34.35... 

K. Motokura, N. Nakagiri, T. Mizugaki, K. Ebitani, and K. Kaneda, Nucleophilic substitution reactions of alcohols with use of montmorillonite catalysts as solid Br0nsted acids, J. Org. Chem., 72 (2007) 6006-6015. 

Nucleophilic substitution reactions of sulfinate ions 106 Addition of sulfinate ions to multiple bonds 108 Radical reactions of sulfinic acids 110... 

As an alternative to the oxidation of sulphides and sulphoxides (see Chapter 10), sulphones can be prepared by the nucleophilic substitution reaction of the sulphinite anion on haloalkanes. In the absence of a phase-transfer catalyst, the reaction times are generally long and the yields are low, and undesirable O-alkylation of the sulphinite anion competes with S-alkylation. The stoichiometric reaction of the preformed tetra-n-butylammonium salt of 4-toluenesulphinic acid with haloalkanes produces 4-tolyl sulphones in high yield [1], but it has been demonstrated that equally good... 

Recently, Lewis-acid-catalyzed nucleophilic substitution reactions of propargyl alcohols have been described. In general, costly transition metals such as Ru, Re, Pd or Au are used in these transformations. At this point Bi(III) salts are believed to be a cheap and environmentally benign alternative. 

A variety of protonic and Lewis acids initiate the cationic polymerization of lactams [Bertalan et al., 1988a,b Kubisa, 1996 Kubisa and Penczek, 1999 Puffr and Sebenda, 1986 Sebenda, 1988]. The reaction follows the mechanism of acid-catalyzed nucleophilic substitution reactions of amides. More specibcally, polymerization follows an activated monomer mechanism. Initiation occurs by nucleophilic attack of monomer on protonated (activated) monomer (XXIV) to form an ammonium salt (XXV) that subsequently undergoes proton exchange with monomer to yield XXVI and protonated monomer. The conversion of XXIV to XXV involves several steps—attachment of nitrogen to C+, proton transfer from... 

On the other hand, when 39 was heated with hydrogen bromide in acetic acid, 1,2-di-<9-acetyl-( 1,3/2,6)-3,4-dibromo-6-(bromomethyl)-l,2-cyclohexanediol (50) was obtained, which was converted into 1,2-di-0-acetyl-( 1,3/2)-3(bromomethyl)-5-cyclo-hexene-l,2-diol (51) by debromination with zinc dust in glacial acetic acid [21]. Hydro-xylation of 51 with osmium tetroxide, and successive acetylation yielded 1,2,3,4-tetra-C>-acetyl-6-bromo-6-deoxy-pseudo-a-DL-glucopyranose (52). Nucleophilic substitution reactions of 52 with sodium acetate gave pseudo-a-DL-glucopyranose pentaacetate (55), which gave pseudo-a-DL-glucopyranose (54) by usual hydrolysis [22]. Alternatively, the pentaacetate 55 was obtained as a minor component in a poor yield by nucleophilic substitutions of 2,3,4-tri-0-acetyl-l,6-dibromo-l,6-dideoxy-pseudo-... 

Most reactions in two-phase systems occur in a liquid phase following the transfer of a reactant across an interface these are commonly known as extractive reactions. If the transfer is facilitated by a catalyst, it is known as phase-transfer catalysis [2]. Unusually, reactions may actually occur at an interface (interfacial reactions) examples include solvolysis and nucleophilic substitution reactions of aliphatic acid chlorides [3 ] and the extraction of cupric ion from aqueous solution using oxime ligands insoluble in water [4], see Section 5.2.1.3(ii). 

Scheme 37 Nucleophilic substitution reaction of 2-bromo-3-hydroxyphospholane 103a with nucleic acids does not give phospha sugar nucleosides...

Kamimura, A. Sasatani, H. Hashimoto, T. Ono, N. Lewis acid induced nucleophilic substitution reaction of/j-riitro sulfides. J. Org. Chem. 1989, 54, 4998-5003. 

Since sulfonation of pyridine iV-oxide is about as difficult as is that of pyridine itself and takes place at the 3-position,17 it has been assumed18 that, in fuming sulfuric acid, pyridine iV-oxide reacts only in the salt form (3), when the prediction is that substitution at C-3 would take place. It is, however, difficult to account for the fact that bromination, even at 110° in the presence of iron powder, does not occur.17 Bromination in chloroform solution in the presence of acetic anhydride and sodium acetate (when the O-acetate is the the probable substrate) take place readily, however, to give 3,5-dibromopyridine JV-oxide.19 The predicted order of nucleophilic reactivity, on the basis of both atom localization energies and ground-state v-electron density calculations, is 4 > 2 > 3. The same order is predicted for the nucleophilic substitution reactions of the salts of pyridine JV-oxide. In actual practice, iV-alkoxypyridinium derivatives undergo nucleophilic attack preferentially at C-2.20-23 The reaction of some pyridine iV-oxides with phosphorus pentachloride may involve the formation... 

WeVe talked at length about the interconversions of acid derivatives, explaining the mechanism of attack of nucleophiles such as ROH, H20, and NH3 on acyl chlorides, acid anhydrides, esters, acids, and amines, with or without acid or base present. We shall now go on to talk about substitution reactions of acid derivatives that take us out of this closed company of compounds and allow us to make compounds containing functional groups at other oxidation levels such as ketones and alcohols. 

Although somewhat less reactive than acid chlorides, anhydrides nonetheless readily react with most nucleophiles to form substitution products. Nucleophilic substitution reactions of anhydrides are no different than the reactions of other carboxylic acid derivatives, even though anhydrides contain two carbonyl groups. Nucleophilic attack occurs at one carbonyl group, while the second carbonyl becomes part of the leaving group. 

Summary of the Nucleophilic Substitution Reactions of Carboxylic Acids and Their Derivatives... 

Like other acid derivatives, acid chlorides typically undergo nucleophilic substitution. Chlorine is expelled as chloride ion or hydrogen chloride, and its place is taken by some other basic group. Because of the carbonyl group these reactions take place much more rapidly than the corresponding nucleophilic substitution reactions of the alkyl halides. Acid chlorides are the most reactive of the derivatives of carboxylic acids. 

Acidic ether cleavages are typical nucleophilic substitution reactions, of the sort discussed in Chapter 11. Primary and secondary alkyl ethers react by an Sn2 mechanism, in which I" or Br" attacks the protonated ether at the less hindered site. This usually results in a selective cleavage into a single alcohol and a single alkyl halide. For example, ethyl isopropyl ether yields exclusively isopropyl alcohol and iodoethane on cleavage by HI, because nucleophilic attack by iodide ion occurs at the less hindered primary site rather than at the more hindered secondary site. 

The effect of a solvent on the rate of the two-step aromatic nucleophilic substitution reactions of primary or secondary amines are sometimes complicated by the acid-base equilibrium (30) and by the fact that the transition state,... 

Nucleophilic Acyl Substitution Reactions of Acid Chlorides... 

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