Silver complexes amides

After successful application of the silver catalyst shown in olefin aziridination (Section 6.1.1), He and coworkers showed that intramolecular amidation was possible with both hydrocarbon-tethered carbamates and sulfamate esters.24 They found that only the Bu3tpy silver complex could catalyze efficient intramolecular amidation, while other pyridine ligands gave either dramatically lower yields or complicated product mixtures. In an interesting control study, both copper and gold were also tested in this reaction. Both the copper and gold Bu tpy complexes can mediate olefin aziridination, but only silver can catalyze intramolecular C-H amidation, indicating that the silver catalyst forms a more reactive metal nitrene intermediate. 

Ferrocenyldiphosphines 3.41 (R = Me2NCH2CH2) are used as ligands in gold-catalyzed asymmetric aldol reactions of a-isocyanoesters or -amides [408, 752, 858, 950], Silver complexes can also be used with the modified phosphine 3.41 (R = (CH2)5 or (CH g) [951, 952]. 

Zhang and coworkers screened a variety of phosphine ligands in the silver-catalysed cyclo addition of the azomethine yhde generated from aryl imines such as (8.202) with dimethyl maleate (8.203), and discovered that the highest ees are achieved with the bis-ferrocinyl amide phosphine (8.204). ° During Zhang s studies it was shown that silver complexes with BINAP are poor catalysts in the addition with dimethyl maleate, however Sansano and coworkers have discovered... 

As a noble metal, silver becomes one of the most important metals in the life of human beings, which has been used as currency and ornaments by humans for thousands of years. Nowadays, silver and its salts have been widely used in photography, electrical equipment, jewelry, as well as transition metal for catalysis in chemistry. In chemical research, silver complexes were usually thought to be low activity and used as either co-catalysts [1, 2] or Lewis acids [3] for decades. In recent years, a wide range of important organic transformation has been catalyzed by silver complexes, including C-H insertion, amination/amidation, fluorination, hydrosilylation, decarboxylation, and so on [4-12]. 

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 45, 71 Sodium amide, in alkylation of ethyl phenylacetate w ith (2-bromo-ethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1 bromobutane to give 2,4-nonanedione, 47, 92 Sodium 2 ammobenzenesulfinate, from reduction of 2 mtrobenzenesul-finic acid, 47, 5... 

Activation of diatyl sulfides with proximal amide functionality, such as 192, with /-BuOCl generates hypervalent sulfuranes 193 (Scheme 25) <1999JST(476)157> see also <2003JOC9574>. Anion exchange of the chloride complex 193 to the perchlorate salt 194 was accomplished by treatment with silver perchlorate. 

Recently the structures of silver(I) complexes with cyclo-(glycyl-L-histidyl), cyclo-(L-methionyl-L-histidyl) and cyclo-(L-histidyl-L-histidyl) were examined using 7H and 13CNMR spectroscopy. The NMR measurements suggested that the silver ion was bound to the sulfur atom of the thioether and to the nitrogen atom of imidazole groups in these cyclic peptides, but not to their amide groups.417... 

Silicon, higher chlorides of, 42 Silicon tetrabromide, 38, 40 Silicon tetrachloride, 44 Silicopropane, octachloro, 44 Silicotungstic acid, 129 analysis, 131 ether complex, 131 Silver, metallic, 4 Silver chloride, reduction of, 3 Silver cyanamide, 98 Silver residues, purification of, 2 Sodium amalgam, 10 Sodium amide, 74 Sodium azide, purification of, 79 Sodium azidodithiocarbonate, 82 Sodium butoxide, 88 Sodium hypochlorite (solution), 90 Sodium iodate, 168 Sodium metaperiodate, 170 Sodium paraperiodate, chlorine method, 169 persulfate method, 170 Strontium amalgam, 11 Sulfur hexafluoride, 121 Sulfuryl chloride, 114... 

Cyano compounds liquid crystals, 12, 278 in silver(III) complexes, 2, 241 Cyanocuprates, with copper, 2, 186 Cyano derivatives, a-arylation, 1, 361 Cyanosilanes, applications, 9, 322 Cyclic acetals, and Grignard reagent reactivity, 9, 53 Cyclic alkenes, asymmetric hydrosilylation, 10, 830 Cyclic alkynes, strained, with platinum, 8, 644 Cyclic allyl boronates, preparation, 9, 196 Cyclic allylic esters, alkylation, 11, 91 Cyclic amides, ring-opening polymerization, via lanthanide catalysis, 4, 145... 

Since ketene is probably the intermediate of the Wolff rearrangement, the choice of solvents dictates the nature of the product. Indeed, water gave carboxylic acids, whereas alcohols or amines led to esters and amides, respectively. These combinations have been applied to the synthesis of more complex molecules. For example, the total synthesis of carbonolide B, a 16-membered macrolide antibiotic, relied on Amdt-Eistert homologation. In this sequence, a protected furanuronic acid was transformed to the corresponding a-diazoketone, which was then converted to its homologous carboxylic ester. The reaction was achieved using catalytic amounts of silver benzoate and excess of triethylamine in methanol (Scheme 3.4).11... 

Allylic amination of allyl halides can also be achieved using lithium and potassium bis(trimethylsilyl)amides [34] and potassium 1,1,3,3-tetramethyldisilazide [35] as the nucleophiles. It has been found that for the reaction of alkyl-substituted allyl chlorides using lithium bis(trimethylsilyl)amides as the nucleophile the allylic amination proceeds smoothly in a SN2 fashion to give /V,Af-disilylamines in high yields when silver(I) iodide was used as an additive. Other metal complexes such as copper ) iodide and other silver(I) salts can also be used as additives for the reaction. 

Sodium cyanamide is used mainly in the production of sodium cyanide that is used extensively in preparing solutions from which metals are electroplated. Sodium cyanide is also used in an extraction process for obtaining gold and silver, because these metals form stable complexes with CN. The sodium cyanamide is obtained by the reaction of sodium amide, NaNH2, with carbon ... 

The solubility of AgCl is therefore sufficient to give [Ag(NH3)2]Cl on treatment with aqueous ammonium carbonate, while AgBr dissolves only in aqueous ammonia, in which Agl is poorly soluble. Aqueous pyridine and substituted pyridines form [Ag(py)]+ and [Ag(py)2]+ ions, but in non-aqueous conditions tetrahedral complexes, such as [Ag(py)4]C104, may be obtained. The tetrahedral acetonitrile adduct [Ag(NCMe)4]+ is also known and is quite stable. There are a number of argen-tate(I) complexes, such as [Ag(NCO)2] and [Ag(ON02)2]- they are linear, with 2-coordinate Ag+.4 Linear coordination is also found in the tetrameric silver amide [Ag N(SiMe3)2 ]4.5... 

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