Aryls carbonyl derivatives

Synthesis of Pyridines. The amiulation of a-aryl carbonyl derivatives with vinamidinium hexafluorophosphate salts in the presence of a base gave access to the corresponding 3-arylpyri-dine. While potassium t-butoxide was used with ketones, the annulation of aldehydes was performed with KHMDS (eq 38). 

Dediazoniations which give aryl-addition or aryl-substitution derivatives of compounds with double bonds are discussed in this and the following section. Reactions at the C or S atom of carbonyl or sulfonyl groups are treated in this section and those at C = C double bonds in Section 10.9. 

DECOMPOSITION OF INORGANIC OXIDES AND SULPHIDES HALIDES AND DERIVATIVES METAL ALKYLS, ARYLS, CARBONYLS AND NITROSYLS... 

In reactions which have some analogy with the interaction of dichloro-carbene/trichloromethyl anions with ketones, 2-dichloromethyloxazolines yield chloro-oxiranes and a-chlorocarbonyl compounds (Scheme 7.18). The formation of the oxiranes is favoured with aldehydes and lower homologue ketones, whereas cyclic ketones and aryl ketones are converted preferentially into the a-chloro carbonyl derivatives [18]. 

Carbonyl dehydrogenase enzymes, model systems, 8, 4 Carbonyl derivatives, a-arylation, 1, 361 Carbonyl-ene reactions... 

As indicated above, the antiknock effect is shown by many compounds. Outstanding among these are the organometallic compounds of many metals. Effective derivatives of many metals include alkyl compounds, aryls, carbonyls, nitrosyls, phosphines, cyclopentadienyls, and many mixed compounds. The aromatic amines are also good antiknock agents, but far less effective than the organometallic compounds. The reason why commercialization efforts were concentrated on tetraethyllead early in the history of antiknock investigations is evident from Table 1, which is a composite of early data 6 8,216). 

The dmuclear carbonyls of group 7 are reduced by alkali metals in THF (equation 41). The pentacarbonylmetalate(—1) anions are appropriate entries into the hydrido- or alkyl (aryl) pentacarbonyl derivatives (see equations 42 and 43). These compounds have pseudooctahedral structures of C4 symmetry with the hydrido or alkyl (aryl) ligand occupying one of the positions within the coordination polyhedron. 

The discussion above emphasizes that the allyl-Ni reagents are quite selective for carbon halogen bonds, especially allyl, vinyl, and aryl halides. At the same time, modest reactivity as nucleophiles toward reactive carbonyl derivatives has been reported.Simple aldehydes, the more reactive ketones (such as cyclopentanone and benzoquinone), and certain epoxides will undergo 1,2-addition of the aUyl ligand to the carbonyl group. Esters, amides, and, most remarkably, acyl halides are inert toward the allyl Ni reagents under conditions where the reagents do not decompose thermally (<80 °C or so). 

Bis(trifluoromethyl)oxazol-5(2//)-ones are carbonyl-group protected, carboxyl-group activated, a-oxoacid derivatives that undergo reaction with benzene-1,2-diamine to yield quinoxa-lin-2(1 7)-one or its 3-alkyl- or 3-aryl-substituted derivatives. ... 

Benzylic amines are resistant to hydrogenolysis under Birch reduction conditions, unless the amine is quaternary, as in the Emde reaction. A means of preserving an aryl carbonyl group is therefore to protect it as an aminal derivative. An illustration is provided by the preparation of aldehyde (213), an important flavor constituent of cumin, as outlined in Scheme 47." ... 

The arylation of enol esters has also been improved (95). Previously a wide range of products were produced including j8-aryl carbonyls, arylated enol esters, styrene, and stilbene derivatives (96). It has also been found that arylated enol esters can be obtained as major products if the reactions are carried out with stoichiometric amounts of aryl mercuric acetate and palladium acetate in anhydrous acetonitrile or in excess enol ester solution. The products are those arising from addition of the phenyl group to the carbons not containing the ester. Thus, with vinyl acetate and phenyl mercuric acetate, the product is the enol acetate of phenyl acetaldehyde ... 

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