Chapter 20: Carboxylic Acids and Their Derivatives

• Identify and name the parent chain that includes the carboxyl group • Identify and name substituents • Assign locant to each substituent giving the carboxyl carbon the lowest number • Assemble substituents alphabetically • Assign configurations to any chiral centers • Replace “e” with suffix −oic acid

Cyclohexanecarboxylic acid

Formic acid

Acetic acid

Propionic acid

Butyric acid

Benzoic acid

Replace the “ic acid” with the suffix −ate

4−5

Reagents • O3 • H2O

Reagents Na2Cr2O7 (sodium dichromate) & H2SO4/H2O or xs CrO3 (chromium trioxide) & H3O+/acetone

Reagents Na2Cr2O7 (sodium dichromate) & H2SO4/H2O

Reagents H3O+ & heat

Reagents • Mg Followed by • CO2 • H3O+ Mechanism Replaces the leaving MgX group withe the carboxyl group; resulting in the addition of one carbon atom

Reagents • LiAlH4 • H3O+ or BH3 (borane) & THF Mechanism Borane is chemoselective and only reduces carboxyl groups in the presence of other carbonyl groups

Any atom that is not carbon or hydrogen

Replace “ic acid” with suffix −yl halide

Replace “acid” with suffix −anhydride If molecule is asymmetrical then the compound is called −oic −oic anhydride

• Add name of the oxygen R −yl group before the parent chain −ate • Replace “ic acid” with suffix −ate

• Replace “ic acid” with suffix −amide • If the nitrogen has substituents, then name them with locant “N”

Replace “ic acid” with suffix −nitrile

Carboxylic acid derivatives are electrophilic at the carbonyl carbon Acid chlorides are the most reactive derivatives Amides are the least reactive derivatives

Can occur under acidic or basic conditions Mechanism A nucleophile attacks a carbonyl carbon and forms a tetrahedral intermediate, the carbonyl can then be reformed by the expulsion of the best leaving group C− and H− are generally not expelled as leaving groups