Ketones, reduction with Grignard reagents

In the general context of donor/acceptor formulation, the carbonyl derivatives (especially ketones) are utilized as electron acceptors in a wide variety of reactions such as additions with Grignard reagents, alkyl metals, enolates (aldol condensation), hydroxide (Cannizzaro reaction), alkoxides (Meerwein-Pondorff-Verley reduction), thiolates, phenolates, etc. reduction to alcohols with lithium aluminum hydride, sodium borohydride, trialkyltin hydrides, etc. and cyloadditions with electron-rich olefins (Paterno-Buchi reaction), acetylenes, and dienes.46... 

Table 3 presents the results of reactions of diisopropyl ketone with Grignard reagents, as studied by Whitmore and George [21]. In these reactions, not only addition and reduction occurs, but also enolization, which finally leads to the recovery of the starting ketone. 

Friedel-Crafts acylation is one of the most important methods of preparing ketones in which the carbonyl group is attached to an aromatic ring. Once formed, these ketones may be converted into secondary alcohols by reduction, into tertiary alcohols by reaction with Grignard reagents, and into many other important classes of compounds, as we shall see. 

Most pyrimidine carbonitriles show normal nitrile chemistry reductive reactions to methylamines by metal hydrides, hydrolytic reactions, reduction to aldehydes and formation of ketones with Grignard reagents. However, in highly electron-deficient pyrimidines, competition may arise between addition to an electrophilic substituent and the electrophilic pyrimidine ring. In the 5-cyano derivative (426), specific attack of organometallics is in the 4-position, with formation of the dihydro derivatives (427) instead of a ketone <83ACS(B)6I3>. 

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