Palladium-catalyzed amination in the synthesis of polyazamacrocycles

The review describes palladium-catalyzed amination of acyclic di- and polyamines with aryl halides with a view to reveal general relations holding in this process. Conditions for the synthesis of macrocycles via catalytic diamination of 1,2- and 1,3-dibromobenzenes, 1,3-dichloro-2-bromobenzene, 2,6- and 3,5-dibromopyridines, 3,3′- and 4,4′-dibromobiphenyls, 2,7-dibromonaphthalene, 1,8- and 1,5-dichloroanthracene, 1,8- and 1,5-dichloroanthraquinones, and bis(haloaryl) derivatives of cyclen, cyclam, and cholanediol are discussed. The possibility for palladium-catalyzed arylation of cyclic polyamines has been demonstrated. Specificity of macrocyclization processes and relations between the yield of macrocycles and the nature of initial compounds are considered, and data on the synthesis of cyclic dimers are given. Applications of polyazamacroheterocycles as optical sensors for metal cations are described using as examples macrocyclic compounds derived from 1,8-disubstituted anthraquinone.     

Palladium-catalyzed amination in the synthesis of macrocyclic compounds containing 1,3-disubstituted adamantane fragments

Palladium-catalyzed amination of 1,3-dibromobenzene, 2,6-dibromopyridine, 3,3′-dibromobiphenyl, 2,7-dibromonaphthalene, and 1,8-dichloroanthracene with an equimolar amount of 2,2′-(adamantane-1,3-diyl)diethanamine resulted in the formation of macrocyclic compounds containing one or several adamantane and one or several aromatic fragments. The reactions of 2,2′-(adamantane-1,3-diyl)diethanamine with excess 1,3-dibromobenzene, 2,6-dibromopyridine, 1,8-dichloroanthracene, and 1,8-dichloroanthraquinone gave the corresponding N,N′-diaryl derivatives. Polyaza macrocycles incorporating adamantane, aromatic, and 4,7,10-trioxatridecane-1,13-diamine fragments, were obtained by palladium-catalyzed amination of the N,N′-diaryl derivatives with 4,7,10-trioxatridecane-1,13-diamine.     

Palladium-catalyzed amination in the synthesis and modification of acyclic oxadiamino cholane derivatives

Palladium-catalyzed reactions of 24-(haloaryloxy)cholanes and 3,24-bis(haloaryloxy)cholanes with excess oxadiamines gave the corresponding mono- and bis(oxadiamino)-substituted cholanes which were subjected to palladium-catalyzed arylation with 1,3-dibromobenzene, 2,6-dibromopyridine, 1,8-dichloroanthracene, 9-bromoanthracene, 1-chloroanthracene, and 1-chloroanthraquinone. The results of these reactions were found to strongly depend on the haloarene nature. The arylation with 1,3-dibromobenzene and 2,6-dibromopyridine led to the formation of new macrocyclic compounds containing one cholane, one arene, and two oxadiamine fragments.     

Palladium-catalyzed amination of allyl alcohols

An efficient catalytic amination of aryl-substituted allylic alcohols has been developed. The complex [(η(3)-allyl)PdCl](2) modified by a bis phosphine ligand, L, has been used as catalyst in the reaction that afforded a wide range of allyl amines in good to excellent yield under mild conditions.     

Palladium-catalyzed amination in the synthesis of macrocycles comprising cholane, polyamine and pyridine units

3,24-Bis(6-chloropyridin-2-yloxy)cholane, obtained from 3,24-cholandiol via a Mitsunobu reaction, was successfully used for the synthesis of a variety of polyazamacrocycles using Pd-catalyzed amination reaction with linear polyamines. The competing formation of cyclodimers and other cyclic oligomers was found to be strongly dependent on the nature of the polyamines employed.     

Palladium-catalyzed amination of aryl nonaflates

The first detailed study of the palladium-catalyzed amination of aryl nonaflates is reported. Use of ligands 2-4 and 6 allows for the catalytic amination of electron-rich and -neutral aryl nonaflates with both primary and secondary amines. With use of Xantphos 5, the catalytic amination of a variety of functionalized aryl nonaflates resulted in excellent yields of anilines; even 2-carboxymethyl aryl nonaflate is effectively coupled with a primary alkylamine. Moderate yields were obtained when coupling halo-aryl nonaflates with a variety of amines, where in most cases the aryl nonaflate reacted in preference to the aryl halide. Overall, aryl nonaflates are an effective alternative to triflates in palladium-catalyzed C-N bond-forming processes due to their increased stability under the reaction conditions.     

Palladium-catalyzed intramolecular aerobic C-H amination of enamines for the synthesis of 2-trifluoromethylindoles

A new palladium-catalyzed C-H amination of aryl enamines for the synthesis of trifluoromethylated indoles is established. The attractive features of this transformation are the use of atom-economical O₂ as the oxidant and easily prepared enamines as substrates. A variety of pharmaceutically important 2-trifluoromethyl indoles can be targeted in moderate to good yields with good functional compatibility.     

Palladium-catalyzed amination in the synthesis of nitrogen and oxygen heterocycles containing fragments of cholane and quinoline

Russian Journal of Organic Chemistry - By Mitsunobu reaction from 3,24-cholanediol and 2-hydroxy-8-chloroquinoline 24-(8-chloroquinolinyl-2-oxy)cholan-3-ol and...     

Palladium-catalyzed amination of quinaldine-5-triflate

Palladium-catalyzed amination reactions of quinoline triflate and the effect of a Pd catalyst, its ligands, solvents, bases, and temperature were studied. This method facilitated an easier pathway for the preparation of aminoquinoline derivatives as potential precursors of new serotoninerg agents.      

Palladium-catalyzed amination and cyclization to heteroannellated indoles and carbazoles

New ortho-bromodiarylamines in the benzo[b]thiophene series were prepared by palladium-catalyzed amination, either in the benzene or in the thiophene ring. These were submitted to palladium-catalyzed cyclization, under different required conditions, to give several differently substituted thieno[3,2-c] or [2,3-b]carbazoles and indolo[3,2-b]benzo[b]thiophenes. This constitutes a novel synthetic route to both tetracyclic systems.     

Palladium-catalyzed asymmetric amination and imidation of 2,3-allenyl phosphates

[reaction: see text] Asymmetric amination of 2,3-allenyl phosphates with nitrogen nucleophiles such as amines, hydroxylamines, and imides can be performed efficiently using a combination of zerovalent palladium complexes and SEGPHOS or MeOBIPHEP ligand, affording the corresponding optically active 1-aminated derivatives with enantiomeric excess of up to 97% ee.     

Palladium-catalyzed nucleomethylation of alkynes for synthesis of methylated heteroaromatic compounds

Herein, we disclosed a novel and efficient palladium-catalyzed nucleomethylation of alkynes for the simultaneous construction of the heteroaromatic ring and methyl group. The 3-methylindoles, 3-methylbenzofurans and 4-methylisoquinolines were obtained in moderate to excellent yields. Notably, this methodology was employed as a key step for synthesis of a pregnane X receptor antagonist, zindoxifene, bazedoxifene and AFN-1252. The kinetic studies revealed that reductive elimination might be the rate-determining step.

A novel palladium-catalyzed nucleomethylation of alkynes is developed, affording 3-methylindoles, 3-methylbenzofurans and 4-methylisoquinolines in moderate to excellent yields.     

Palladium-catalyzed amination of aryl halides on solid support

[reaction: see text] The first examples of the Pd(0)-catalyzed amination of aryl halides using Rink-resins as nitrogen source are described. Pd(2)dba(3)/BINAP/NaO-t-Bu was found to be the most efficient catalyst/base system, while a solvent mixture of dioxane and tert-butyl alcohol was shown to enhance the selectivity toward the desired monoarylation. Moderate to good yields and excellent purities of the amination products were found with electron-poor aryl halides, while electon-rich aryl halides failed to react under these conditions.     

Palladium-catalyzed amination of chloro-substituted 5-nitropyrimidines with amines

A concise and efficient approach was developed for the synthesis of mono-substituted and di-substituted pyrimidines products via palladium-catalyzed amination of chloro-substituted 5-nitropyrimidines and amines. This synthetic methodology can produce various di-substituted pyrimidines in high yields with good functional group tolerance, and provide a complementary tool for the syntheses of important intermediates of nucleosides and purines with bioactivities.     

Palladium-catalyzed regioselective oxidative amination of alkenes: an efficient route to the synthesis of pyrrolocoumarin and pyrroloquinolone derivatives

Palladium-catalyzed IBX-induced intramolecular oxidative amination of alkenes has been utilized for the synthesis of pyrrolocoumarin and pyrroloquinolone derivatives in excellent yields in a short reaction time.     

Palladium-catalyzed amination of aryl and heteroaryl tosylates at room temperature

Mild palladium-catalyzed aminations of aryl tosylates and the first aminations of heteroaryl tosylates are described. In the presence of the combination of L2Pd(0) (L = P(o-tol)3) and the hindered Josiphos ligand CyPF-t-Bu, a variety of primary alkylamines and arylamines react with both aryl and heteroaryl tosylates at room temperature to form the corresponding secondary arylamines in high yields with complete selectivity for the monoarylamine. These reactions at room temperature occur in many cases with catalyst loadings of 0.1 mol % and 0.01 mol % in one case, constituting the most efficient aminations of aryl tosylates by nearly 2 orders of magnitude. This catalyst is made practical by the development of a convenient method to synthesize the L2Pd(0) precursor. This complex is stable to air as a solid. In contrast to conventional relative rates for reactions of aryl sulfonates, the reactions of aryl tosylates are faster than parallel reactions of aryl triflates, and the reactions of aryl tosylates are faster than parallel or competitive reactions of aryl chlorides.     

Palladium-catalyzed amination of chloromethylnaphthalene and chloromethylanthracene derivatives with various amines

Palladium-catalyzed amination of chloromethylnaphthalene and chloromethylanthracene derivatives to produce naphthylamines and anthrylamines in satisfactory to good yields has been developed. The unprecedented amination reactions proceeded smoothly under mild conditions in the presence of Pd(PPh(3))(4) as a catalyst.