Reaction of Organometallic Reagents with Carboxylic Acid Derivatives

13 Reaction of Organometallic Reagents with Carboxylic Acid Derivatives 

Organometallic reagents react with carboxylic acid derivatives (RCOZ) to form two different products, depending on the identity of both the leaving group Z and the reagent R-M. The most useful reactions are carried out with esters and acid chlorides, forming either ketones or 3° alcohols. 

Throughout this discussion, keep in mind that RLi and RMgX are very reactive reagents, whereas RgCuLi is much less reactive. This reactivity difference makes selective reactions possible. 

13A Reaction of RLi and RMgX with Esters and Acid Chlorides 

Both esters and acid chlorides form 3° alcohols when treated with two equivalents of either Grignard or oi anolithium reagents. Two new carbon-carbon bonds are formed in the product. 

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Reaction of organometallic reagents with carboxylic acid derivatives... 

The reactions of several carboxylic acid derivatives with organomagnesium and organolithium compounds were described in Section 14-12. The key step in these reactions is addition of the organometallic compound, as R60MS , to the carbonyl group. For a Grignard reagent,... 

Predict the products and propose mechanisms for the reactions of carboxylic acid derivatives with reducing agents, alcohols, amines, and organometallic reagents. Q Propose multistep syntheses using acid derivatives as starting materials and intermediates. 

This chapter will discuss methods for the preparation of esters, acid chlorides, anhydrides, and amides from carboxylic acids, based on acyl substitution reactions. Acyl substitution reactions of carboxylic acid derivatives will include hydrolysis, interconversion of one acid derivative into another, and reactions with strong nucleophiles such as organometallic reagents. In addition, the chemistry of dicarboxylic acid derivatives will be discussed, as well as cyclic esters, amides, and anhydrides. Sulfonic acid derivatives will be introduced as well as sulfate esters and phosphate esters. Finally, nitriles will be shown to be acid derivatives by virtue of their reactivity. 

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