Oxygen compounds acetal substitution

Studies on the electrochemical oxidation of silyl-substituted ethers have uncovered a rich variety of synthetic application in recent years. Since acetals, the products of the anodic oxidation in the presence of alcohols, are readily hydrolyzed to carbonyl compounds, silyl-substituted ethers can be utilized as efficient precursors of carbonyl compounds. If we consider the synthetic application of the electrooxidation of silyl-substituted ethers, the first question which must be solved is how we synthesize ethers having a silyl group at the carbon adjacent to the oxygen. We can consider either the formation of the C-C bond (Scheme 15a) or the formation of the C-O bond (Scheme 15b). The formation of the C Si bond is also effective, but this method does not seem to be useful from a view point of organic synthesis because the required starting materials are carbonyl compounds. 

Metal-Oxygen Compounds. The addition of metal-oxygen compounds to olefins is exemplified by the addition of mercuric acetate to olefins in hydroxylic solvents (83). Both cis and trans adducts may be obtained depending upon the structure of the olefin. Where trans addition is hindered by substitutents, cis addition appears to occur (3, 94). Ward and Henry have obtained kinetic evidence that the addition of mercuric acetate to ethylene in aqueous solution involves the prior formation of a 7r-ethylene complex. Presumably, trans addition results from attack by external solvent or ion, and cis addition results from ligand addition (101),... 

Catalytic data were also compared at the same conversion, namely 5%, as shown in Figure 4. It can be seen that, with the introduction of to substitute Mo in the Keggin anion, selectivity to propene dropped, while those in acetic acid and COx increased. Exception to this trend was the Wo sample, which gave relatively high selectivities to propene and acetic acid, i.e relatively low selectivity in COx and other oxygenated compounds. 

In addition to the conventional mixed acids commonly used to produce DNT, a mixture of NO2 and H2SO4 (8), a mixture of NO2 and oxygen (9), and just HNO (10) can also be used. TerephthaUc acid and certain substituted aromatics are more amenable to nitrations using HNO, as compared to those using mixed acids. For compounds that are easily nitratable, acetic acid and acetic anhydride are sometimes added to nitric acid (qv). Acetyl nitrate, which is a nitrating agent, is produced as an intermediate as follows ... 

The reactivity of mercury salts is a fimction of both the solvent and the counterion in the mercury salt. Mercuric chloride, for example, is unreactive, and mercuric acetate is usually used. When higher reactivity is required, salts of electronegatively substituted carboxylic acids such as mercuric trifiuoroacetate can be used. Mercuric nitrate and mercuric perchlorate are also highly reactive. Soft anions reduce the reactivity of the Hg " son by coordination, which reduces the electrophilicity of the cation. The harder oxygen anions leave the mercuric ion in a more reactive state. Organomercury compounds have a number of valuable synthetic applications, and these will be discussed in Chapter 8 of Part B. 

Mercuric acetate can be used to substitute sulfur to oxygen in compound 116 (Equation 26) <2000JME199>. 

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