Carbon as a nucleophile Grignard reagents

H and FT are poor leaving groups, reaction irreversible and get protonation 

Amides seem to behave differently, with complex metal hydride reduction giving an amine, effectively converting the carbonyl group to a methylene (see Section 7.11). 

This behaviour results from initial formation of an intermediate with two potential leaving groups, an amide anion R2N and the aluminate anion (OAlHs). Aluminate is the better leaving group, and its loss produces an iminium cation that is also subject to further reduction. This gives us the amine product. 

Although at first glance the behaviour of some of these carbonyl compounds towards nucleophiles might seem anomalous, closer consideration shows there is a logical explanation for the reactions observed. Furthermore, if we understand the underlying mechanisms, these reactions become predictable. 

The reaction of carbon nucleophiles derived from organometallics with carboxylic acid derivatives follows closely the reactions we have already encountered in Sections 6.3.2 and 7.6.2. Organometallics 

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