Carbonyl compounds with organometallic reagents

We will now discuss the reactions of carbonyl compounds with organometallic reagents, another class of nucleophiles. 

B Reaction of a,p-Unsaturated Carbonyl Compounds with Organometallic Reagents... 

A,A-disubstituted derivatives 1-5. Amination of Group 1, 2, 11 and 12 organometallic compounds and a-metallated carbonyl compounds with these reagents takes place by a direct introduction of the R1R2N+ group to carbanions and enolates and for completion the reactions require only hydrolytic work-up (Scheme 3). 

The interaction of carbonyl-containing compounds with organometallic reagents (Expts 5.39 to 5.43). 

THE INTERACTION OF CARBONYL-CONTAINING COMPOUNDS WITH ORGANOMETALLIC REAGENTS... 

Alternatives which are more useful for /3-hydroxy carbonyl compounds are organometallic reagents. Organozinc reagents (67) react with aldehydes and ketones but not with esters so they can be made from a-halo esters. This, the Reformatsky reaction, has the advantage that the -halo esters are easily made (see Chapter 7). 

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. 

The formation of chiral alcohols from carbonyl compounds has been fairly widely studied by reactions of aldehydes or ketones with organometallic reagents in the presence of chiral ligands. Mukaiyama et al. 1081 obtained excellent results (up to 94% e.e.) in at least stoichiometric addition of the chiral auxiliary to the carbonyl substrate and the organometallic reagent. 

A carbonyl compound with two alkyl groups bonded to the carbonyl group, (p. 443) (Gilman reagent) An organometallic reagent used to couple with an alkyl halide, (p. 451)... 

To show how these general principles of nucleophilic substitution and addition apply to carbonyl compounds, we are going to discuss oxidation and reduction reactions, and reactions with organometallic reagents—compounds that contain carbon-metal bonds. We begin with reduction to build on what you learned previously in Chapter 12. 

Carbonyl compounds that also contain N - H or O - H bonds undergo an acid-base reaction with organometallic reagents, not nucleophilic addition. 

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