Carboxylic acid anhydrides with alcohols

Carbery et al. reported the novel design and rhodium-catalyzed synthesis of a heli-cenoidal DMAP analog bearing a 4-dialkylaminopyridine unit and a helical scaffold (Scheme 10.9) [11]. This compound could be employed successfully as a chiral Lewis base organocatalyst in the kinetic resolution of secondary alcohols with carboxylic acid anhydrides (Scheme 10.10) [11]. 

The classical chemical reaction of acylation of alcohols with carboxylic acid anhydrides can also be carried out enantioselectively in the presence of enzymes [83]. This can be regarded as an example of esterification reaction displaced toward the products... 

Esterification with carboxylic acid anhydrides (Section 15.8) Carboxylic acid anhydrides react with alcohols to form esters in the same way that acyl chlorides do. 

Esters from the reaction of alcohols with carboxylic acids, acid halides and anhydrides. 

Esters from the reaction of Alcohols with Carboxylic acids, Acid Halides, and Anhydrides. 

It should finally be pointed out that trimethylsilyl ethers can also be transformed directly into other functionalities. Oxidation with NBS leads to ketones and aldehydes, treatment with LiAllWAlCb results in deoxygenation of the alcohol, reaction with carboxylic acid anhydrides in the presence of BF3-OEt2 produces esters and on treatment with PhsP Brj acid bromides are foimed directly from TMS esters. ss... 

Phenols react with carboxylic acid anhydrides and acid chlorides to form esters. These reactions are quite similar to those of alcohols (Section 17.7). 

Esters can be prepared by reaction of alcohols with carboxylic acids under acidic catalysis but can be hydrolyzed in either acid or basic solution. They can also be prepared by reaction of alcohols with acid chlorides or anhydrides. 

The alcohol groups of carbohydrates undergo chemical reactions typical of hydroxyl functions They are converted to esters by reaction with acyl chlorides and carboxylic acid anhydrides... 

Much more important than these reactions, however, are the reactions of CDI and its analogues with carboxylic acids, leading to AAacylazoles, from which (by acyl transfer) esters, amides, peptides, hydrazides, hydroxamic acids, as well as anhydrides and various C-acylation products may be obtained. The potential of these and other reactions will be shown in the following chapters. In most of these reactions it is not necessary to isolate the intermediate AAacylazoles. Instead, in the normal procedure the appropriate nucleophile reactant (an alcohol in the ester synthesis, or an amino acid in the peptide synthesis) is added to a solution of an AAacylimidazole, formed by reaction of a carboxylic acid with CDI. Thus, CDI and its analogues offer an especially convenient vehicle for activation of... 

The reactive 1-acyl-3-alkylimidazolium species also plays a role in acylation of alcohols with carboxylic anhydrides or carboxylic acid chlorides using 1-substituted imidazoles as catalysts.[145] In this case the reactive species is formed in situ ... 

The reaction with carboxylic acid and acid anhydride is carried out in the presence of a small amount of concentrated sulphuric acid. The reaction is reversible, and therefore, water is removed as soon as it is formed. The reaction with acid chloride is carried out in the presence of a base (pyridine) so as to neutralise HCl which is formed during the reaction. It shifts the equilibrium to the right hand side. The introduction of acetyl (CH3CO) group in alcohols or phenols is known as acetylation. Acetylation of salicylic acid produces aspirin. 

In trying to formulate a reaction mechanism for the catalysis, the well known reaction of aluminum alcoholates with carboxylic anhydrides was used as a basis (14). For example, phthalic anhydride, maleic anhydrides, and carbon dioxide, will react so that the acid anhydride pushes itself between the metal atom and the alkoxy groups, thus separating them. This results in forming neutral aluminum salts of the monoalkyl carboxylic acids. It is possible, of course, for the conversion to proceed incompletely, having two alkoxy groups bound to the aluminum, thus having only 1 mole of acid anhvdride react on 1 mole of aluminum alcoholate. 

Fluorinated alkylisocyanates and isothiocyanates add alcohols, mercaptans, and amines to yield stable 1 1 adducts [76]. When the reaction is performed with carboxylic acids, the anhydrides first formed decompose to give A -fluoroalky-lated amides [77]... 

The at complex from DIB AH and butyllithium is a selective reducing agent.16 It is used tor the 1,2-reduction of acyclic and cyclic enones. Esters and lactones are reduced at room temperature to alcohols, and at -78 C to alcohols and aldehydes. Acid chlorides are rapidly reduced with excess reagent at -78 C to alcohols, but a mixture of alcohols, aldehydes, and acid chlorides results from use of an equimolar amount of reagent at -78 C. Acid anhydrides are reduced at -78 C to alcohols and carboxylic acids. Carboxylic acids and both primary and secondary amides are inert at room temperature, whereas tertiary amides (as in the present case) are reduced between 0 C and room temperature to aldehydes. The at complex rapidly reduces primary alkyl, benzylic, and allylic bromides, while tertiary alkyl and aryl halides are inert. Epoxides are reduced exclusively to the more highly substituted alcohols. Disulfides lead to thiols, but both sulfoxides and sulfones are inert. Moreover, this at complex from DIBAH and butyllithium is able to reduce ketones selectively in the presence of esters. 

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