In reactions of ketones with

Electrophilic catalysis by acyl cations in reactions of ketones with nitriles... 

The comparison indicates that the enol of an a-diazocarbonyl compound may be a (relatively ) stable entity. Unfortunately, however, the situation looks less favorable on the basis of our present knowledge on diazoethene (5.28). As discussed in Section 2.9, 2,2-dialkyl derivatives of this compound are likely to be formed in reactions of ketones with dimethyl diazomethylphosphonate (2-95), but they lose N2 very rapidly. The resulting unsaturated carbenes can be trapped or undergo a 1,2-alkyl shift to give 1,2-dialkylethynes. 2,2-Difluorodiazoethene, however, is detectable at a... 

The reaction of ketones with peroxy acids is both novel and synthetically useful. An oxygen from the peroxy acid is inserted between the carbonyl group and one of the attached carbons of the ketone to give an ester. Reactions of this type were first described by Adolf von Baeyer and Victor Villiger in 1899 and are known as Baeyer—Villiger oxidations. 

Thiohydantoin 9 was obtained from the treatment of carbonyl 1 with carbon disulfide and ammonium cyanide in aqueous methanol. The transformation could also be carried out step-wise, that is, treatment of 1 with ammonium cyanide to form aminonitrile 10 followed by reaction with carbon disulfide to produce thiohydantoin 9. Alternatively, 5,5-disubstituted 4-thiohydantoins could be prepared by the reaction of ketones with ammonium monothiocarbamate and sodium cyanide. ... 

The absolute configuration of the cycloaddition product obtained by the reaction of ketones with activated dienes catalyzed by (S)-t-Bu-BOX-Cu(II) (S)-21b points also to an intermediate in which the geometry around the central copper atom is square-planar similar to 26 above, and that the diene approaches the carbonyl functionality in an endo fashion. 

The Henry reaction of ketones with nitroalkanes in the presence of etbylenediamine gives allylic nitro compounds, which give a,fi-imsanirated carbonyl compounds via the Nef reaction fEq. 6.30. ... 

Reduction of Ketones and Enones. Although the method has been supplanted for synthetic purposes by hydride donors, the reduction of ketones to alcohols in ammonia or alcohols provides mechanistic insight into dissolving-metal reductions. The outcome of the reaction of ketones with metal reductants is determined by the fate of the initial ketyl radical formed by a single-electron transfer. The radical intermediate, depending on its structure and the reaction medium, may be protonated, disproportionate, or dimerize.209 In hydroxylic solvents such as liquid ammonia or in the presence of an alcohol, the protonation process dominates over dimerization. Net reduction can also occur by a disproportionation process. As is discussed in Section 5.6.3, dimerization can become the dominant process under conditions in which protonation does not occur rapidly. 

The reaction of ketones with diazomethane sometimes leads to a ring-expanded ketone in synthetically useful yields.79 The reaction occurs by addition of the diazomethane, followed by elimination of nitrogen and migration. 

In the reaction of ketones with thionyl chloride the intermediate sulfinyl (or sulfenyl) chloride can cyclize on to an aromatic ring located two carbon atoms away giving benzo[b]thiophenes (48) (Scheme 7).54 Additional... 

The migration aptitudes in the reaction of ketones with peracetic acid in acetic acid as a solvent are in the order -anisyl > phenyl > >-nitro-phenyl.82 Cyclohexyl and phenyl are about equal in migration aptitude... 

The reactions in which the methyl ketone loses a primary proton are all fast reactions, and the direction of the reaction is determined by the fact that an electron-releasing alkyl group slows down the removal of the secondary proton from the methylene group. On the other hand a slow reaction, like the base-catalyzed reaction of ketones with dimethyl sulfate in ether, gives a product corresponding to the removal of a proton from the more alkylated carbon.418... 

In contrast to the high regioselectivity and good yields of electroreductive intramolecular coupling reactions of ketones with multiple bonds shown in Schemes 34 to 37, the yields of interm olecular coupling reactions have been very low until recently. However, by using carbon fiber electrodes, intermolecular coupling reactions have... 

The a-alkylation of enolates derived from ketones with alkyl halides is a very important and frequently used method for forming new carbon-carbon bonds in organic synthesis [40]. Yet, if the a-alkylation of enolates derived from ketones with alkyl halides can be replaced by the direct reaction of ketones with alcohols, this method would provide a very useful waste-free, green route to a-alkylation, producing no side products other than water. 

Oximes are usually prepared by reaction of ketones with hydroxylamine while, especially in industrial processes, ketoximes are synthesized by the reaction shown in Scheme... 

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