Organometallic compounds reactions with ketones

Two other acid derivatives may also be converted to ketones by reaction with organometallic compounds. Grignard reagents add to nitriles to give imine salts (Section 14.4.3), which are hydrolyzed to ketones in the reaction work-up. In Figure 19.27, again the disconnected bond is highlighted in red. Remember than many aliphatic nitriles are readily prepared by displacement... 

The most general synthetic route to ketones uses the reaction of carboxylic acids (or their derivatives) or nitriles with organometallic compounds (M.J. Jorgenson, 1970). Lithium car-boxylates react with organolithium compounds to give stable gem-diolates, which are decom-... 

Zirconium tetrachloride is instantly hydrolyzed in water to zirconium oxide dichloride octahydrate [13520-92-8]. Zirconium tetrachloride exchanges chlorine for 0x0 bonds in the reaction with hydroxylic ligands, forming alkoxides from alcohols (see Alkoxides, METAl). Zirconium tetrachloride combines with many Lewis bases such as dimethyl sulfoxide, phosphoms oxychloride and amines including ammonia, ethers, and ketones. The zirconium organometalLic compounds ate all derived from zirconium tetrachloride. 

Reaction of organometallic compounds with enamine salts have been successfully used for the synthesis of some natural products (256). Thus reaction of the immonium salt of 0-alkylated enamino ketone 122 with isobutyllithium affords the compound 169. 

Nitriles are similar in some respects to carboxylic acids and are prepared either by SN2 reaction of an alkyl halide with cyanide ion or by dehydration of an amide. Nitriles undergo nucleophilic addition to the polar C=N bond in the same way that carbonyl compounds do. The most important reactions of nitriles are their hydrolysis to carboxylic acids, reduction to primary amines, and reaction with organometallic reagents to yield ketones. 

As an extension of the reaction of sulphinates with organometallic compounds, the Claisen-type condensation between ketone enolate anions 101 and arenesulphinates may be considered. It was found161,162 that this reaction provides an interesting synthetic approach to a-ketosulphoxides 102 (equation 54 Table 9). 

For a list of preparations of ketones by the reaction of organometallic compounds with carboxylic esters, salts, anhydyrides, or amides, with references, see Ref. 568, pp. 685, 693. 

Reactions of aromatic aldehydes and ketones containing a tellurenyl halide group in an o-position with organometallic compounds provide an approach to less accessible o-alkyltellurocarbonyl compounds (72BSF3559, 78T655, 81JOM(208)11) (Scheme 14). 

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