Nucleophiles aldehydes and ketones

Among the electrophilic reaction parmers of the enamine nucleophiles, aldehydes and ketones are arguably the most important class. The addidon of an enamine to a carbonyl compound affords aldol products after hydrolysis (Scheme 13). In this process, one or two new stereogenic centers and one carbon-carbon bond are formed. 

Carbonyl electrophiles are obviously a very important group of electrophiles that react successfully with a spectrum of carbon nucleophiles. Among carbonyl electrophiles, however, large differences in reactivity are observed. Acid chlorides are very reactive electrophiles whereas esters and amides are much weaker and fail to react with several classes of carbon nucleophiles. Aldehydes and ketones are probably the most widely utilized groups of carbonyl electrophiles and exhibit moderate electrophilic reactivity. No matter what carbonyl electrophile is used, however, it reacts by nucleophilic addition to the carbonyl carbon to produce a tetrahedral intermediate. The ultimate reaction product reflects subsequent chemistry of the tetrahedral intermediate. 

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