Nucleophiles examples

The mfluoromethyl group activates the fluorine in position 4 ofperfluorotolu ene toward reaction with carbon nucleophiles Examples on che use of perfluoro-toluene as an arylation agent abound, and in all cases, the 4-fluonne atom is replaced predommantly or exclusively [% 87,88,89, 90 (equation 48) In perjluoromesity-lene, the aromatic fluorine atoms are activated toward Ar reaction, and a reaction... 

Sulfur compounds with divalent sulfur functionalities are much more prone to dioxirane oxidation on account of their higher nucleophilicity compared to the above-presented oxygen-type nucleophiles. Examples of this type of dioxirane oxidation abound in the literature. Such a case is the oxidation of thiols, which may be quite complex and afford a complex mixture of oxidation products, e.g. sulfinic acids, sulfonic acids, disulfides, thiosulfonates and aldehydes , and is, therefore, hardly useful in synthesis. Nevertheless, the oxidation of some 9i/-purine-6-thiols in the presence of an amine nucleophile produces n >( -nucleoside analogs in useful yields (equation 19). This reaction also displays the general chemoselectivity trend that divalent sulfur functionalities are more reactive than trivalent sp -hybridized nitrogen compounds P. 

They are, however, reactive carbon nucleophiles. Examples of enolates include anionic derivatives of aldehydes, ketones, acid derivatives, and dicarbonyl compounds. 

The construction of complex intermediates from simple and readily available starting materials has been accomplished using the electrocyclic ring-opening reaction of halocyclopropanes. This is typically achieved through interception of the cationic haloallyl intermediate by solvent, the silver(I) counteranion, or some alternate tethered heteroatom or carbon-based nucleophile. Examples of these processes are described below. 

Fig. 8. 3. Zwitterion mechanism of the decomposition of neutral carbonic acid (derivatives) in a heterocumulene and a hetereo-nucleophile—examples carbonic acid (B), carbonic acid monomethylester (E), carbonic acid mono-tert-butylester (H), carbamic acid (K), and urea (M).

The addition of oxygen and chloride nucleophiles to dienes transiently activated by catalytic Pd is a practical process for production of 1,4-disubstituted 2-alkenes from 1,3-dienes however, it is not useful with carbon nucleophiles. Examples of carbon nucleophile addition to Fe° and Mo complexes show useful selectivity, but only in stoichiometric processes, and few applications have appeared. 

Diazo ketones also possess an electrophilic diazo group, and hence are susceptible to diazo-coupling reactions with suitable soft nucleophiles. Examples are given in equations (11) and (12). Phospha-zines such as (19) are useful synthetic intermediates in their own right. The carbon terminus of the 1,3-dipole possesses nucleophilic properties and can participate in aldol-type reactions with the particularly electrophilic carbonyl groups in 1,2-di- and 1,2,3-tri-carbonyl compounds. Intramolecular condensations occur with greater ease (equation 13). Reaction of diazo ketones of the type summarized in equations (9)-(12) have been thoroughly reviewed. ... 

In common with other aromatic systems, halogen can be displaced from azapentalenes by nucleophiles. Examples include displacement of Br by or in derivatives of 402, by CN in... 

There is good evidence that some nucleophilic substitution reactions do involve a single electron transfer, but the best established use a slightly different mechanism. These are the SrnI reactions, with the subscript RN standing for radical nucleophilic. Examples are the reaction of the nitronate anion 4.14 with p-nitrobenzyl chloride 4.15, 251 and the reaction of the pinacolone enolate 4.16 with bromobenzene.252 The former might have been a straightforward SN2 reaction, but actually takes the S l pathway because the nitro groups make the electron transfer exceptionally easy. The latter cannot take place by a conventional Sn2 reaction, because aryl (and vinyl) halides are not susceptible to direct displacement, and the S l pathway overcomes this difficulty. 

If the Nuc/Base is a strong base and not sterically hindered, we next consider whether it is a good nucleophile. Examples of strong bases that are also good nucleophiles... 

There is some dependence on the basicity of the nucleophile, measured by the pK value of its corresponding acid particularly in series of structurally related nucleophiles. Examples are in the reactions of m- and p-substituted anilines with l-chloro-2,4-dinitrobenzene [1] and of substituted phenoxide ions with halogenonitrobenzenes [9]. Similarly, the reactivities of m- and p-substituted thiophenoxide ions with l-chloro-2,4-dinitrobenzene closely parallel their basicities [56]. 

Alkynes can also be activated to attack by carbon nucleophiles. Examples include the reaction between propiolate esters 6.187 and arenes (Scheme 6.89). ... 

Element state (radius. A) nature type strength nucleophilicity Examples... 

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