Nucleophiles addition with

Unsaturated Hydrocarbons. Olefins from ethylene through octene have been converted into esters via acid-catalyzed nucleophilic addition. With ethylene and propjiene, only a single ester is produced using acetic acid, ethyl acetate and isopropyl acetate, respectively. With the butylenes, two products are possible j -butyl esters result from 1- and 2-butylenes, whereas tert-huty esters are obtained from isobutjiene. The C5 olefins give rise to three j iC-amyl esters and one /-amyl ester. As the carbon chain is lengthened, the reactivity of the olefin with organic acids increases. 

The research groups of Mariano and West developed a photoinduced electrocydi-zation/nucleophilic addition sequence. Thus, irradiation of N-alkylpyridinium perchlorates as 5-19 in an aqueous solution led to the aziridine cations 5-20, which react in a nucleophilic addition with OH to give the isolable azabicyclo[3.1.0]hex-2-enols 5-21. These can be further transformed by a nucleophilic ring-opening of the aziridine moiety under acidic conditions to lead to useful unsymmetrically trans,trans-trisubstituted cyclopentenes 5-22 (Scheme 5.5) [10]. 

Diethylamine can readily undergo nucleophilic addition with 1,2-allenyl sulfoxides to afford 2-diethylamino-2-enyl sulfoxides 181, which can be easily converted to a-hydroxy ketones 182 or /3-keto sulfoxides 183 [94]. 

Electron transfer sensitization allows either the radical cation or the radical anion of an aromatic alkene to form as desired, which finally results in nucleophile addition with Markovnikov and anti-Markovnikov regiochemistry. In an apolar solvent, the tight radical ion pair undergoes a stereoselective reaction when the electron-accepting sensitizer is chiral (Figure 3.10). ... 

Substituted snoutan-9-ones (61a) undergo nucleophilic additions with the same facial selectivity as the corresponding norsnoutanones (61b). However, the selectivity is markedly reduced, apparently owing to electrostatic effects in (61a), and hyperconjugative interactions in (61b). ... 

Reflecting its electronegative character, C q readily undergoes nucleophilic additions with various nucleophiles [7]. Apparently the most fundamental C-C bond forming reaction is the reaction with alkyllithium or Grignard reagents, giving the monoalkylated derivative of l,2-dihydro-C6o after protonation of the initially formed alkyl-Cso carbanion [48]. 

Triazole can undergo nucleophilic addition with aldehydes, but the reaction is reversible and the products cannot be isolated. They can be trapped, however, with acid chlorides (Scheme 7) <90CL351>. 

Besides electrophilic addition, terminal alkynes also perform acid-base type reaction due to acidic nature of the terminal hydrogen. The formation of acetylides and alkynides (alkynyl Grignard reagent and aUcylnyllithium) are important reactions of terminal alkynes (see Section 4.5.3). Acetylides and alkynides undergo nucleophilic addition with aldehydes and ketones to produce alcohols (see Section 5.3.2). 

Less satisfactory results have been frequently encountered in the related asymmetric cycloaddition of a vinyl epoxide to an isocyanate as in Scheme 8E.30 [160]. The modest enantioselectivities of this process are indicative of the competitive intramolecular nucleophilic addition with enantioface exchange. When the oxazolidinone was generated from an achiral substrate, somewhat higher enantioselectiviites were obtained presumably due to superposition of the enantioselection obtained in the ionization step. 

The K-region oxides undergo nucleophilic addition with OH", C032", water, amines, and mercaptides.88,140 The second-order rate constants for the reactions of OH", water, and primary and secondary amines with 1 at 30°C and with ethylene oxide at 25°C141 can be simply related by Eq. (6),2 which shows that the sensitivity of the two oxides to the nature of the nucleophile is similar and that the arene oxide is more reactive. 

The carbanion undergoes nucleophilic addition with the carbonyl group of a second molecule of ethanal, which leads to formation of the condensation product. 

There are two reaction pathways for addition of neutral and anionic nucleophiles to p-1 (Scheme 39) direct nucleophile addition with rate constant kNu (M 1 s 1) and specific acid-catalyzed nucleophile addition kHNu (M 2 s 1), through the protonated intermediate p-H-l+ with an acidity constant and microscopic rate constants of ks and k- u (Scheme 39) for addition of solvent or nucleophilic anion to form product. Eqs. (2a) and (2b) show the... 

One mechanistic possibility for this thioacetalation reaction invokes furanoside ring-opening of 17, initiated by complexation with boron trifluoride etherate (Scheme 12.9). Oxonium ion 28 could then get intercepted by the ethanethiol to produce 29. After further complexation with BF3, in the manner shown, thionium ion formation can again occur to give 30, which can then engage in yet another nucleophilic addition with the ethanethiol to produce 31 after protonation. 

This is generally done during an experimental work up where the products of the reaction are dissolved in a water immiscible organic solvent. Aqueous sodium bisulphite is then added and the mixture is shaken thoroughly in a separating funnel. Once the layers have separated, any aldehydes and methyl ketones will have undergone nucleophilic addition with the bisulphite solution and will be dissolved in the aqueous layer as the water soluble salt. The layers can then be separated. If the aldehydes or methyl... 

Halogenated quinolines very often undergo nucleophilic addition with BuLi, so must be lithiated with LDA.175-279 The regioselectivity of their reactions parallels that of the pyridines, and similar halogen migrations are observed 323 324... 

Hydride reduction of a ketone or aldehyde is another example of nucleophilic addition, with hydride ion (H ) serving as the nucleophile. Attack by hydride gives an alkox-ide that protonates to form an alcohol. 

C10Hy, and the naphthyne radical cation, C10H6, with H, O and N have been reported, as well as reactions of these ions with H2, CO, H20 and NH3 [49]. Differences in reactivity were observed that could be correlated with the multiplicities of the reactant C10HJ cation. The radical C10Hg cation was found to react with H, O and N atoms but not with H2, CO, H20 and NH3. In contrast, the closed-shell C10HJ cation was found to be essentially unreactive with atoms but was seen to associate via nucleophilic addition with most of the molecules studied. The atom and molecule reactions of the naphthyne radical cation C HJ were found to be similar to those observed for the C10Hg radical cation, except for the reaction with ammonia which proceeded at a moderate rate. 

The electrophilic methylene ligand undergoes nucleophilic additions with PPhs, py, and CN-f-Bu. It reacts with O and S donors to give [ReCp2( -H2CE)]+ (E = O, S) and with N2CHTMS to form the olefin complex [ReCp2( ] -H2C=CHTMS)]+. 

The net result is that the n bond is broken, two new o bonds are formed, and the elements of H and Nu are added across the 7t bond. Nucleophilic addition with two different nucleophiles— hydride (H ") and carbanions (R >— is discussed in Chapter 20. 

Scheme 8. General mechanism of nucleophilic addition with subsequent elimination of water.

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