Arylation ketones

Reactivity factors in additions to carbon-hetero multiple bonds are similar to those for the tetrahedral mechanism of nucleophilic substitution. If A and/or B are electron-donating groups, rates are decreased. Electron-attracting substituents increase rates. This means that aldehydes are more reactive than ketones. Aryl groups are somewhat deactivating compared to alkyl, because of resonance that stabilizes the substrate molecule but is lost on going to the intermediate ... 

Me3Si(OSiHMe) OSiMe3, A1C13 (aryl ketones) EtsSiH, BF3 (ketones, aryl aldehydes)... 

With unsymmetrical methyl ketones arylation occurred at the primary carbon. Where two yields are stated the figure in parentheses is the isolated yield and the other is analytical (e.g. determined by GLC or H NMR). Reaction in the dark, catalyzed by iron(II) sulfate. dBoth halogens replaced. 

Aromatic ketones arylations, 10, 140 asymmetric hydrogenation, 10, 50 G—H bond alkylation, 10, 214 dialkylzinc additions, 9, 114-115 Aromatic ligands mercuration, 2, 430 in mercury 7t-complexes, 2, 449 /13-77-Aromatic nitriles, preparation, 6, 265 Aromatic nucleophilic substitution reactions, arene chromium tricarbonyls, 5, 234... 

Vinyl-l//-isochromenes can be prepared in moderate yield by a palladium-catalyzed coupling of ( )-(3-(2-bromo-phenyl)allyloxy)tenM)i i r l)si Iyl derivatives 157 with ketones. The reaction proceeds via initial ketone arylation to furnish the intermediate 158 followed by intramolecular cyclization of the ketone enolate onto the tethered allylic system (Scheme 50) <2000CG1675>. 

A great variety of tertiary enamines derived from aliphatic ketones, aryl alkyl ketones and functionalized ketones were reduced by formic acid, most of them in good yields, even in the presence of other functional groups, such as carbonyl, cyano and other carbon-carbon double bonds205 (Scheme 137). 

Selective reduction of aldehydes. In the absence of radical initiators, tributyltin hydride does not ordinarily reduce carbonyl groups. However, when slurried in cyclohexane with dried silica gel (activated by heating at 220° under reduced pressure), this hydride reduces aldehydes and ketones to alcohols in high yield. The rate of reduction is aldehydes > dialkyl ketones > aryl alkyl ketones > diaryl ketones. Thus it is possible to reduce aldehydes selectively. The function of Si02 apparently is that of a mild acid catalyst. 

M-16 0 Nitro compound, sulfoxide M-42 CH2CO Methyl ketone, aryl acetate... 

M-16 NHj Sulfonamide, carboxamide M-42 C3H, Butyl or isobutyl ketone, aryl... 

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