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Anilines nucleophiles

A variety of rhodium complexes, including [Rh(CO)2Cl]2 and [Rh(COD)Cl]2 when used in combination with a variety of bisphosphine ligands, will catalyze the ring opening of vinyl epoxides in the presence of aniline nucleophiles [19, 20]. These reactions occur under very mild and neutral conditions (at room temperature or with mild heating) and are highly regio- and stereoselective. In all cases, nucleophilic attack occurs at the allylic epoxide carbon atom and proceeds with inversion of stereochemistry (Scheme 9.11). [Pg.187]

The relative importance of N-substituted arylamines for the construction of biologically significant molecules, particularly pharmaceuticals and agrochemicals, prompted the extension of rhodium-catalyzed allylic amination to aniline nucleophiles (Tab. 10.6) [41, 42]. The N-arylsulfonyl-protected anihnes were again optimal for high selectivity, analogous to that observed with the N-toluenesulfonyl-N-aLkylamines. [Pg.204]

Aniline nucleophiles readily participate in this type of ring-closure process under palladium catalysis (Pd(OAc>2, BINAP, and CS2CO3 in hot toluene) without resort to protecting groups when an aryl iodide is used <2005T61>. [Pg.218]

Modification of the butyl linker moiety was then studied on SP, treating 9.26 with Ml (symmetrical anhydrides or diacids, 10 representatives. Fig. 9.19) to give the resin-bound acids 9.34, which were pooled, reduced to alcohols 9.35, and brominated to give the alkyl bromides 9.36. The resin was split into 60 portions and treated with M2 (the same 60 thiophenol and aniline nucleophiles as for L13) to give the 600-member pool library L14 made of 60 pools of 10 individuals (Fig. 9.19). The library quality... [Pg.443]

It is not possible to construct an invariant nucleophilicity order because different substrates and different conditions lead to different orders of nucleophilicity, but an overall approximate order is NH2 > PhaC > PhNH (aryne mechanism) > ArS > RO > R2NH > ArO > OH > ArNHi > NH3 > 1 > Br > Cl > H2O > ROH. As with aliphatic nucleophilic substitution, nucleophilicity is generally dependent on base strength and nucleophilicity increases as the attacking atom moves down a column of the periodic table, but there are some surprising exceptions, for example, OH, a stronger base than ArO , is a poorer nucleophile. In a series of similar nucleophiles, such as substituted anilines, nucleophilicity is correlated with base strength. Oddly, the cyanide ion is not a nucleophile for aromatic systems, except for sulfonic acid salts and in the von Richter (13-30) and Rosenmund-von Braun (13-8) reactions, which are special cases. [Pg.869]

Aniline nucleophiles were used in the early days in the Menschutkin reaction with alkyl halides in a variety of solvents1-6 and have made important contributions in the development of the Hammett equation7. However, due to the narrow range of basicity (pX a = 1.02-6.08 for 4-NO2-4-NH2 substituted anilines8, and 0.67-5.89 for 4-N02-4-... [Pg.537]

Nevertheless, aniline nucleophiles have made continued, important contributions in organic synthesis and in studies of organic reaction mechanisms, which constitute the major subjects of this chapter. [Pg.538]

Ando and coworkers conducted isotope effect studies (entry 11) on the direct displacement reaction of benzyl arenesulfonates with dimethylaniline (DMA)38. They found that an electron-withdrawing substituent in the substrate (Y = 3-Br) caused the TS to shift to a later position along the reaction coordinate, which is consistent with that predicted by the Thornton rule (or anti-Hammond effect). The anilinolysis of phenylethyl arenesulfonates (entries 12 and 13) proceeds also by an SN2 mechanism. The reaction was found to proceed by a dissociative SN2 mechanism with a relatively small degree of aryl participation. The fraction of the phenonium ion intermediate captured by the aniline nucleophile in the aryl-assisted pathway has been shown to increase with a stronger nucleophile, and a four-center TS in an intermolecular SNi mechanism is suggested for the aryl-assisted pathway39,40. Under the same reaction conditions, benzylamine nucleophiles react at a rate ca two times faster than that of anilines. [Pg.543]

In this reaction the TS is considered to have a structure in which nearly complete bond formation occurs between the nucleophile and cation formed in an ion-pair preequilibrium. For relatively strong electron-donating substituent Y, the resonance delocalization of the cationic charge leads to a substantial negative charge accumulation on the reaction center carbon (Scheme 3), which in turn leads to an electron acceptance by the aniline nucleophile, and hence px becomes positive. [Pg.547]

TABLE 10. Kinetic isotope effects with deuteriated aniline nucleophiles... [Pg.575]

A number of other examples of useful applications of KIEs involving deuteriated aniline nucleophiles are reported15e g. Elucidation of the TS structures is facilitated by means of nucleophile KIEs in conjunction with the sign and magnitude of the cross-interaction constants. [Pg.577]

Scheme 11.3 Preferential external attack of the aniline nucleophile leads to inversion of stereochemistry at the benzyl palladium intermediate. Scheme 11.3 Preferential external attack of the aniline nucleophile leads to inversion of stereochemistry at the benzyl palladium intermediate.
An interesting tandem intermolecular/intramolecular hydroamination reaction of cycloheptatriene with substituted anilines has been developed by Hartwig for the synthesis oftropene derivatives [34]. As shown in Eq. (1.14), the coupling of 30 with 31 provided 32 in 73% yield. The mechanism of this transformation is believed to involve acid-assisted formation of an q -pentadienylpalladium complex 33, which is then captured by the aniline nucleophile to afford the allylpalladium intermediate 34. Intramolecular attack of the aniline nitrogen on the allylpalladium moiety affords the observed heterocycle. [Pg.7]

The kinetics and mechanism of the aminolysis of phenyl-substituted phenyl phosphonyl chlorides (136) with anilines (135) were investigated in MeCN at 55.0 °C. Very sensitive variation of /Oy(5/Oy2>0) with the change of substituent on the nucleophile Sax) led to a large negative cross-interaction constant, pxY = Spy)/ Sox) = —1.31. The secondary kinetic isotope effects observed with deuteriated aniline nucleophiles were of the inverse type (/th/ d = 0.61-0.87), and small A// (1.6-9.7kcalmor ) and large negative A5 (—43 to —65 e.u.) values were... [Pg.80]

Amide and electron-poor aniline nucleophiles have also been employed in heteroaryl halide amination reactions. For example, an organic synthesis procedure was recently reported for the synthesis of ethyl 4-[(6-chloropyridin-3-yl)amino] benzoate via Ai-arylation of ethyl 4-aminobenzoate with 2-chloro-4-iodopyridine (Eq. 32) [220]. Beletskaya has illustrated that bromoindole derivatives can be coupled with amides utilizing either Xantphos or 3,5-(Cp3)2Xantphos (22) as the ligand in good yield (Eq. 33) [169]. [Pg.19]


See other pages where Anilines nucleophiles is mentioned: [Pg.861]    [Pg.653]    [Pg.1033]    [Pg.544]    [Pg.545]    [Pg.547]    [Pg.549]    [Pg.549]    [Pg.558]    [Pg.565]    [Pg.575]    [Pg.575]    [Pg.577]    [Pg.116]    [Pg.224]   


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Allylic with aniline nucleophiles

Aniline, basicity nucleophilicity

Anilines nucleophilic cleavage with

Aromatic nucleophilic displacement aniline

Nucleophilic aromatic substitution aniline derivatives

Nucleophilic reactions anilines

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