N-aryl amines

The reaction of amines with aryl halides requires a catalyst in most cases to initiate the reaction. There are several approaches that result in N-aryl amines. Treatment of cyclohexylamine with p-MeC6H4B(OH)2 and Cu(OAc)2 gave the N-aryl amide in 63% yield. Aryl halides react with amines in the presence of palladium... 

N-Aryl amination, or the Buchwald-Hartwig reaction, has proven to be a useful and versatile method to obtain aryl amines, which are of great synthetical and industrial interest [145]. The first examples of carbene/palladium-catalyzed amination of aryl halides showed that in situ-generated catalyst could efficiently mediate the coupling of aryl halides with primary and secondary amines, imines and indoles [ 146-148]. Even if most of these reactions could be carried out at room temperature with aryl iodides and bromides, elevated temperatures were required in order to couple aryl chlorides. 

N Alky] and N aryl imines have received the most attention in the literature, but significant research has also been performed in the area of "activated imines, that is, imines with electron withdrawing substituents at N. In addition to having different reactivity from N alkyl and N aryl imines, these compounds are intrinsically open to further functionalization after hydrogenation. The first of these compounds to be reduced enantioselectively were the N tosyl amines. In contrast to the related reaction with N alkyl and N aryl amines, the asymmetric hydrogenations of N tosyl amines are most often catalyzed by complexes of palladium. 

Limitations Most of the catalysts currently require imines derived from aromatic amines. N aryl amines are thus easily made (as in the synthesis of SCH48461) but if primary amines are the target, the N aryl group has to be removed (as in the synthesis of colchinol). 

N-Arylation. Amines are arylated with the aid of CuO nanoparticles under basic conditions (KOH, DMSO, air, 80-110°). Another protocol indicates the use ofFe(acac)2 as cocatalyst, as demonstrated by an effective in A-arylation of pyrazole. ... 

N-Arylation. Amines are perfluoroarylated with perfluoroarenes in THE The amino group is attached to the p-position in the reaction involving perfluorotoluene or pentafluoropyridine. Generally, primary amines are more reactive but secondary amines also undergo perfluoroarylation at a higher temperature and with added triethylamine. 

R—N=N Aryl diazonium 10ns are formed by treatment of primary aromatic amines with nitrous acid They are ex tremely useful in the preparation of aryl halides phenols and aryl cyanides... 

N Nitroso amine (Section 22 15) A compound of the type R2N—N=0 R may be alkyl or aryl groups which may be the same or different N Nitroso amines are formed by ni trosation of secondary amines... 

I-Substituted 3,5-Dinitro-4-pyridonyl, 360 SPECIAL -NH PROTECTIVE GROUPS N-Alkyl and A-Aryl Amines... 

Bei N-Aryl-carbamidsaureestern werden dagegen die N-Hydroxymethyl-amine erhalten z.B.1 ... 

Grubbs reported the synthesis of several N, N -aryl substituted imidazolinium salts 35 from chiral Ar,AT -aryl diamines obtained by palladium-catalyzed amination of the appropriate aryl bromide with (li, 2i )-diaminocyclohexane... 

Overman LE, Owen CE, Pavan MM, Richards CJ (2003) Catalytic asymmetric rearrangement of allylic N-aryl trifluoroacetimidates. A useful method for transforming prochiral allylic alcohols to chiral allylic amines. Org Lett 5 1809-1812... 

Nielsen DJ, Cavell KJ (2006) Pd-NHC complexes as catalysts in telomerization and aryl amination reactions. In Nolan SP (ed) N-Heterocyclic carbenes in synthesis. WUey-VCH, Weinheim, pp 73-102... 

As for the reaction with alcohols N -trifluoroacetylbenzotriazole is conveniently used for trifluoroacetylation of primary or secondary alkyl or aryl amines to give excellent yields of trifluoroacetamides [95al... 

A more recent publication by Weigand and Pelka has disclosed a polymer-bound Buchwald-Hartwig amination [40], Activated, electron-deficient aryl halides were coupled with conventional PS Rink resin under microwave irradiation. Subsequent acidic cleavage afforded the desired aryl amines in moderate to good yields (Scheme 7.22). Commercially available Fmoc-protected Rink amide resin was suspended in 20% piperidine/N,N-dimethylformamide at room temperature for 30 min to achieve deprotection. After washing and drying, the resin was placed in a silylated microwave vessel and suspended in dimethoxyethane (DME)/tert-butanol... 

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