AgOAc oxidant

The preparation of isocoumarins from the oxidative coupling of benzoic acids with alkynes in MeOH with oxidant AgOAc is catalysed by [Cp lrCl2]2 complex. Alkyl alkynes are more reactive than aryl alkynes. The DFT calculations of intermediates and transition states reveal that C-H activation occurs via an acetate-assisted meehanism, the C-H activation is not turnover limiting and the AgOAc oxidizes the reduced form of the catalyst via an Ir(I)-lr(ll)-Ir(IIl) sequence. ... 

By using ruthenium complexes derived from [RuCl2(p-cymene)]2/AgOAc, oxidative alkenylations of amidines with substituted acrylates provided diversely substituted 1-iminoisoindolines (Eq. (7.52)) [48]. The resulting product was proposed to form in a process of oxidative alkenylation, intramolecular aza-Michael addition, and dehydrogenation. 

Reaction of commercially available 3-chlorotetronic acid 762, obtained by pyrolysis of methyl 2,4-dichloroacetoacetate at 140 °C in vacuo [235], with o-phenylene-diamine affords, after cyclization-oxidation with AgOAc, the quinoxaline lactone 763 in 69% yield [234] (Scheme 5.83). 

TPA-Ru04 (4.5 mg, 0.013 mmol) is added to the nitro compound (0.13 mmol), A-methyl-morpholine-iV-oxide (22.7 mg, 0.194 mmol), AgOAc (43 mg, 0.258 mmol), K2CO, (90 mg, 0.65 mmol) and powdered 4A molecular sieves (0.1 g) in MeCN (2 ml). The mixture is stirred for 10 h at 40° C and Et20 (5 ml) is then added. Filtration through Celite and evaporation of the filtrate yields the ketone. 

The cross-coupling reaction of diaryl tellurides with alkenes in MeOH in the presence of Pd " catalyst, EtjN and AgOAc as oxidant, gives the corresponding aryl-substituted (Z)-aUcenes in good yields. ... 

The nitrile oxides were generated using KF or AgOAc or 4 A molecular sieves (66). 

Selective silylation of ribonucleosides.2 Only the 5 -hydroxyl group of ribonucleo-sides is silylated by reaction with the reagent in THF in the presence of silver nitrate. On addition of pyridine to the reaction, 2, 5 -disilyl derivatives are formed in 80-90% yield. The actual reagent may be r-butyldimethylsilyl nitrate. Highly selective 3, 5 -disilylation can be achieved in the presence of several silver salts (AgN03, AgC104, and AgOAc) in the presence of either DABCO or 4-nitropyridine N-oxide. 

Allylic acetoxylation.1 The combination of r-butyl hydroperoxide and Se02 has been used for allylic hydroxylation of alkenes (8, 64-65), but this system is not useful for oxidation of cycloalkenes. Allylic acetoxylation of cycloalkcnes is possible, but in modest yield, with PdCl2 and AgOAc, which probably form a reactive species such as [PdCl(OAc)] . This system can be used in catalytic amounts in the presence of t-butyl hydroperoxide for a reoxidation step. The yield is improved by addition of TcO, which seems to accelerate the oxidation. The most satisfactory ratios of... 

If AgOAc is reacted with porphyrins in glacial acetic acid, Ag(II) porphyrins are formed directly [88,90]. Whether this is due to oxidation by protons [88], or more likely, by aerial dioxygen, is an open question. Anyway, the formation of the Ag(II) porphyrin even occurs when AgOAc is used in just 1.2 molar excess to the porphyrin in acetonitrile [91]. Instead of pyridine, dimethyl formamide [63] is frequently used as a solvent for the preparation of Ag(II) porphyrins [92-95]. With certain water-soluble porphyrin ligands, the disproportionation reaction (9a) is retarded, and the corresponding disilver(I) porphyrins can be studied in solution [96]. 

X2 (Cla, Bra, I2) in HOH, ROH, RCOOH, (RC0)20 X2 in cone. H2S04 or H2S207 with or without Ag2S04 X2 with Al2Xe, AgOAc X2 with acidic oxidant HXO3, HNO3 O II... 

Alcohols with a hydrogen in the 8 position can be cychzed with lead tetraace-tate. ° The reaction is usually carried out at 80°C (most often in refluxing benzene), but can also be done at room temperature if the reaction mixture is irradiated with uv light. Tetrahydrofurans are formed in high yields. Little or no four- and six-membered cyclic ethers (oxetanes and tetrahydropyrans, respectively) are obtained even when y and s hydrogens are present. The reaction has also been carried out with a mixture of halogen (Br2 or I2) and a salt or oxide of silver or mercury (espe-cially HgO or AgOAc), with iodosobenzene diacetate and I2, and with ceric... 

Oxidations. This reagent combination (the amine oxide being IV-methylmorpholine N-oxide) has been used to oxidize organoboranes to fiimish carbonyl compounds, and in the presence of AgOAc and 4A molecular sieves it oxidizes secondary nitroalkanes to ketones. A modified reagent consists of a polymer-linked trimethylammonium perruthenate and trimethylamine oxide. ... 

DeBoef and co-workers have reported a similar reaction, wherein direct C-H to C-H indole-arene cross-coupling can be controlled through the use of a particular oxidant (Scheme 34) [53,54], The basis of their selectivity concept is the formation of different polyvalent clusters between the Pd(OAc)2 and the AgOAc or Cu(0 Ac)2 oxidants respectively, and the subsequent reactivity of these complex in the aryla-tion reaction. The same group also demonstrated the utility of an intermolecular C-H to C-H coupling reaction. 

The catalytic oxidative coupling of two dissimilar arenes is also possible, for example, iV-acetyl indoles, or benzofurans, with benzene and other simple arenes. The mechanism involves sequential metallations in the two rings. The regioselectivity can be controlled by the choice of oxidant, Cu(OAc)2 favouring C-3 and AgOAc, C-2 substitution in 1-acetylindole. ... 

Interestingly, this selectivity could be inverted towards predominant arylations at position C-2 when using AgOAc as a sacrificial oxidant (Scheme 9.52) [131]. It is... 

Regiochemical dependency in the oxidative coupling of A-acetylindole with arenes on the added oxidant [AgOAc vs. Cu(OAc)2] is a remarkable phenomenon. ... 

The Woodward cis-dihydroxylation1 involves the oxidation of an olefin to a c/s-diol via a two-step reaction sequence. First, treatment of an olefin 1 with I2, AgOAc and wet HOAc gives monoacetate 2. Hydrolysis of 2 under basic conditions then affords cw-diol 3. 

In 1958, Woodward and Bratcher reported a study on the cis-dihydroxylation of steroid intermediate 4.1 They attempted to use OSO4 as the oxidant, but obtained the undesired cis-diol diastereomer 5 with that reagent. Thus, they developed a two-step dihydroxylation sequence using I2, AgOAc, and HOAc followed by KOH. Not only did this procedure work remarkably well, it afforded the desired diol diastereomer 8 in which dihydroxylation had occurred on the more sterically hindered p face of 4. Thus, treatment of 4 with I2, AgOAc, and HOAc afforded a mixture of acetates 6 and 7. Basic hydrolysis of 6 and 7 with KOH in methanol then gave diol 8 in 71% yield after recrystallization. 

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