PALLADIUM-CATALYZED COUPLING OF ARYL HALIDES

The palladium-catalyzed formation of sulfides can generate polyphenylene sulfide from a dithiol and a dibromoarene, or from 4-bromobenzenethiol (Equation (38)).17 In 1984 Asahi Glass obtained patents for the formation of this polymer in the presence of palladium and nickel catalysts.125,126 In addition, Gingras reported palladium-catalyzed couplings of aryl halides and thiols to form discrete phenylene sulfide oligomers.127,128 A number of polyphenylene sulfide wires, ranging from dimeric to pentameric structures, were prepared by the palladium coupling, albeit in modest yields ... 

Muller and co-workers reported the three-component one-pot synthesis of various pyrimidines through the in situ generation of unsaturated carbonyl compounds. The palladium catalyzed coupling of aryl halides bearing electron withdrawing substituents 7 with propargyl alcohols 8 produced unsaturated carbonyl compounds 9 after isomerization, which condensed with amidines 10 to form triaryl pyrimidines 11 . 

Tunney, S.E. and Stille, J.K., Palladium-catalyzed coupling of aryl halides with (trimethylstannyl)diphenylphosphine and (trimethylsilyl)diphenylphos-phine, /. Org. Chem., 52, 748, 1987. 

Palladium-catalyzed aryl-aryl coupling, 66, 70 PALLADIUM-CATALYZED COUPLING OF ARYL HALIDES, 66, 67 Palladium sponge, 66, 54... 

The functionalization of the ring nitrogen atom in aziridines is traditionally achieved in classical substitution reactions. A recent article, however describes the transition metal catalyzed introduction of different aryl groups onto the aziridine core (8.37.), According to the reported results both the palladium catalyzed coupling of aryl halides and the copper... 

Transition metal-catalyzed cross-coupling is now recognized to be one of the most powerful carbon-carbon bond-formation reactions [1], The palladium-catalyzed coupling of aryl halides or their synthetic equivalents, for example aryl triflates, with arylmetals is very often employed in the synthesis of biaryl molecules, whose skeletons are found in a wide range of important compounds including natural products and organic functional materials [1-3]. 

Palladium, benzylchlorobis(triphenylphosphine)-, trans-, 67, 86 Palladium-catalyzed aryl-aryl coupling, 66, 70 PALLADIUM-CATALYZED ALLYLIC AMINATION, 67,105 PALLADIUM-CATALYZED CHLOROACETOXYLATION, 67, 105 PALLADIUM-CATALYZED COUPLING OF ACID CHLORIDES WITH ORGANOTIN REAGENTS, 67, 86 PALLADIUM-CATALYZED COUPLING OF ARYL HALIDES, 66, 67 PALLADIUM-CATALYZED syn-ADDITION OF CARBOXYLIC ACIDS,... 

John Hartwig, from Yale, is not only one of the very leaders of the new generation in or-ganometallic chemistry, but also possibly the best presently known expert in the synthetic and mechanistic aspects of palladium-catalyzed coupling of aryl halides with nucleophiles. His chapter (No. 4) covers the broad area of palladium-catalyzed animation of aryl halides and sulfonates. 

The palladium-catalyzed coupling of aryl halides and other aryl substrates with aromatic rings containing a suitable leaving group is now well... 

The first reports of palladium-catalyzed arylation (equation 39) of azoles occurred with catalysts bearing DPPF as the ligand125. These reactions of indole, pyrrole and carbazole with activated aryl halides were carried out at 80-100°C. The reactions of indole and pyrrole with unactivated aryl halides such as bromobenzene, 4-bromo-r -butylbenzene and 3-bromoanisole occurred in high yields. However, the conditions of these reactions were more severe than those typically necessary to conduct palladium-catalyzed coupling of aryl halides with amines (equation 40). 

Biaryl structures are found in a wide range of important compounds, including natural products and organic functional materials [8,80,81]. One of the most common and useful methods for preparing biaryls is the palladium-catalyzed coupling of aryl halides with arylmetals (Scheme 1, mechanism A). On the other hand, aryl halides have been known to couple directly with aromatic compounds as formal nucleophiles under palladium catalysis. While the intramolecular cases are particularly effective, certain functionalized aromatic compounds such as phenols and aromatic carbonyl compounds, as well as... 

Cross-coupling reactions have also been examined in water using amphiphilic PS-PEG resin-supported palladium complexes. Palladium-catalyzed coupling of aryl halides with aryl(or alkenyl)boronic acids (the so-called Suzuki-Miyaura coupling) took place in aqueous alkaline solution in the presence of polymeric catalyst 59 at 25 °C to give the biaryls in excellent yields [90,... 

Larock, R.C., Leung, W.Y. and Stolz-Dunn, S. (1989) Synthesis of aryl-substituted aldehydes and ketones via palladium-catalyzed coupling of aryl halides and non-allyUc unsaturated alcohols. Tetrahedron Lett., 30, 6629-32. 

The use of ligated copper catalysts has dramatically improved the coupling of aryl halides with amides—the Goldberg reaction. . This reaction has been studied intensively because of the utility of the products and the limitations in scope and efficiency of the palladium-catalyzed coupling of aryl halides with amides. Moreover, it is the process that occurs with the broadest scope when conducted with certain ancillary ligands. 

Scheme 3.44b).Another efficient palladium-catalyzed intramolecular carbopalladation-cyclization cascade toward tetra- and pentacyclic N-fused heterocycles was developed in 2010. This transformation proceeds via the palladium-catalyzed coupling of aryl halides with internal propargylic esters or ethers followed by a 5-endo-dig cyclization leading to polycyclic pyrrolo-heterocycles in moderate to excellent yields (Scheme 3.44c). 

SCHEME 3.6 Palladium-catalyzed coupling of aryl halides, isocyanide, and amines. 

The palladium-catalyzed coupling of aryl halides with a sodium aryl sulfinate afforded symmetrical and unsymmetrical diaryl sulfones in good to excellent yield (Scheme 5.47) [69]. A common palladium(O) compound was used as the metal source, and XantPhos served as the supporting/stabilizing ligand. A base was also needed for this chemistry, and... 

---