Reactions of Acid Derivatives with Organometallic Reagents

When the organohthium reagent is inexpensive, as in the case of phenyllithium, it is customary to add two equivalents of the reagent direcdy to the carboxylic acid. The first equivalent reacts with the carboxylic acid to form the lithium carboxylate salt. The second equivalent reacts with the carbonyl carbon atom of the carboxylate ion. 

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Mechanism 21-13 Hydride Reduction of an Ester 1015 Mechanism 21-14 Reduction of an Amide to an Amine 1016 21-9 Reactions of Acid Derivatives with Organometallic Reagents 1017 Mechanism 21-15 Reaction of an Ester with Two Moles of a Grignard Reagent 1018... 

Reactions of Acid Derivatives with Organometallic Reagents... 

REACTION OF ACYL DERIVATIVES WITH ORGANOMETALLIC REAGENTS Acid Chlorides... 

Aldehydes and ketones have a central role in organic synthesis, and efficient procedures for their preparation are of great importance. Such compounds are synthesized in a number of ways, including hydration or hydroboration-oxidation of alkynes (Eqs. 16.10 and 16.11, respectively, and Chap. 11) and reaction of carboxylic acids or their derivatives with organometallic reagents or reducing agents... 

Nucleophilic 1,4- and 1,6-additions of cuprates and other organometallic reagents to acceptor-substituted dienes have been utilized extensively in target-oriented stereoselective synthesis52-61. Schollkopf and coworkers55 reported the diastereoselective 1,6-addition of a bislactim ether-derived cuprate to 3,5-heptadien-2-one (90% ds equation 17). The corresponding reactions of dienoates were conducted with the lithiated bislactim ether and proceeded with diastereoselectivities of >99% ds (equation 18)56 the adducts could be converted easily into diastereo- and enantiomerically pure amino 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. 

A diazonium salt reacts with copper(I) cyanide to form a benzonitrile. Because a cyano group can be hydrolyzed to a carboxylic acid, reduced to an amine or aldehyde, or converted to a ketone with organometallic reagents, this reaction provides easy access to a wide variety of benzene derivatives using chemistry described in Section 22.18. 

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