Nucleophilic Acyl Substitution Reactions of Carboxylic Acids

Nucleophilic Acyl Substitution Reactions of Carboxylic Acids 

Conversion of Carboxylic Acids into Acid Chlorides 

Carboxylic acids are converted into acid chlorides by treatment with thionyl chloride, SOCU. 

The reaction occurs by a nucleophilic acyl substitution pathway in which the carboxylic acid is first converted into a chlorosulfite intermediate, thereby replacing the -OH of the acid with a much better leaving group. The chlorosulfite then reacts with a nucleophilic chloride ion. You might recall from Section 17.6 that an analogous clilorosulfite is involv ed in leactioii of an alcohol with SOCI2 to yield an alkyl chloride. 

The following structure represents a tetrahedral alkoxide ion intermediate formed by addition of a nucleophile to a carboxylic acid derivative. Identify the nucleophile, the leaving group, the starting acid derivative, and the ultimate product. 

Strategy A nucleophilic acyl substitution involves the substitution of a nucleophile for a leaving group in a carboxylic acid derivative. Identify the leaving group (Cl- in the case of an acid chloride) and the nucleophile (an alcohol in this case), and replace one by the other. The product is isopropyl benzoate. 

Problem 21.6 Predict the product of each of the following nucleophilic acyl substitution reactions  

CHAPTER 21 I Carboxylic Acid Derivatives and Nucleophilic Acyl Substitutions 

Some nucleophilic acyl substitution reactions of carboxylic acids. 

CHAPTER 21 Carboxylic Add Derivativos and Nucleophilic Acyl Substitutiont 

---

Nucleophilic Acyl Substitution Reactions of Carboxylic Acid Derivatives (Chapter21)... 

A. Nucleophilic acyl substitution reactions of carboxylic acids (Section 21.3). 

Many nucleophilic acyl substitution reactions of carboxylic acids are acid-initiated. For example, in esterification, the carbonyl group is protonated, alcohol attacks to form the tetrahedral intermediate, proton transfers occur, and water leaves. 

H Nucleophilic Acyl Substitution Reaction of Carboxylic Acids... 

---