CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID...
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ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
CONCEPT: COOH DERIVATIVES AND NUCLEOPHILIC ACYL SUBSTITUTION
Carboxylic acid derivatives are defined as any carbonyl with a single electronegative group (-Z) in the α-position.
● These follow unique nucleophilic mechanism due to the presence of a leaving group, called NAS.
● By definition, they can ALL be hydrolyzed to a carboxylic acid using water with acid or base.
□ Nitriles also fall into this category due to their ability to be hydrolyzed
= -Cl, -COOR
-OR, -OH, - NH3
General Carbonyl Mechanisms:
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: ESTER NOMENCLATURE
The word “ester” is not found in ester nomenclature, making these difficult to recognize.
● Name as an ________________ + ___________________________
EXAMPLE: Correctly name the following structure.
EXAMPLE: Correctly draw the following molecule.
Isopropyl formate
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: ACID CHLORIDE NOMENCLATURE
Common: Replace “ic acid” with the suffix -yl chloride
IUPAC: Replace “e” with the suffix -oyl chloride
EXAMPLE: Provide both the correct IUPAC and common name for the following molecule.
EXAMPLE: Correctly draw the following molecule.
γ-ethylvaleryl chloride
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: ANHYDRIDE NOMENCLATURE
Alphabetize acids, then replace the word acid with ___________________
● If you have two identical –R groups, name as alkynoic anhydride
EXAMPLE: Provide both the correct name for the following molecule.
EXAMPLE: Provide both the correct name for the following molecule.
Formic anhydride
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: NITRILE NOMENCLATURE
Add suffix _________________ to the alkane name
● Do not drop the ”e”
● Substituents are located using _______
EXAMPLE: Correctly name the following structure.
EXAMPLE: Correctly draw the following molecule.
2-amino-4-bromohexanenitrile
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: AMIDE NOMENCLATURE
Replace “e” with the suffix _______________
● R groups on the nitrogen are named as substituents on the
--N or –N, N positions
EXAMPLE: Correctly name the following structure.
EXAMPLE: Provide both the correct name for the following molecule.
N, N-dibenzylacetamide
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: NUCLEOPHILIC ACYL SUBSTITUTION – THE THREE RULES
Most of the formulas governing the conversion of carboxylic acid derivatives can be simplified into the following 3 Rules:
RULE #1 The general reactions for these conversions are as follows:
RULE #2 More reactive acyl compounds can be easily _______________________ into less reactive ones.
The reactivity of carbonyls toward NAS depends upon the strength of the __________________________
RULE #3 The Carboxylic Acid Conversions
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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PRACTICE: Determine the major product for the following reaction.
PRACTICE: Determine the major product for the following reaction.
PRACTICE: Determine the major product for the following reaction.
PRACTICE: Determine the major product for the following reaction.
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: FISCHER ESTERIFICATION— MECHANISM
Also known as acid-catalyzed esterification, this is one of the more important mechanisms in this course.
General Reaction:
Mechanism:
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: ACID-CATALYZED ESTER HYDROLYSIS— MECHANISM
The exact reverse of Fischer esterification.
General Reaction:
Mechanism:
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: BASE-CATALYZED ESTER HYDROLYSIS— MECHANISM
Also known as saponification, this is one of the more important mechanisms in this course.
General Reaction:
Mechanism:
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: BASE-CATALYZED TRANSESTERIFICATION— MECHANISM
Occurs when an ester is exposed to an alkoxide base with a dissimilar alkyl group.
● Can be avoided by only exposing esters to alkoxides with the same –R group as the ester
General Reaction:
Mechanism:
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: LACTONES, LACTAMS AND CYCLIZATION REACTIONS
Hydroxycarboxylic acids and aminocarboxylic acids can be made to cyclize, forming lactones and lactams, respectively.
● 5 and 6-membered rings can cyclize spontaneously
Lactones and Lactams:
EXAMPLE: Provide the correct structure for the following cyclization reaction and name the new functional group.
Formation of cyclic anhydrides and imides:
Cyclic Anhydrides and Imines
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: SPECIFIC CARBOXYLIC ACID CONVERSIONS
Synthesis of Acid Chloride:
Synthesis of Amides:
Dehydration of Amides:
Hydrolysis of Nitriles:
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: ALDEHYDES VIA REDUCING AGENTS
All of the reducing agents we have learned so far are so powerful that they yield alcohols.
● We need to use milder reducing agents to yield aldehydes.
1. Typical strong reduction of carbonyls is accomplished via the use of ____________________
2. We can reduce the power of the reducing agent by making it sterically hindered: _________________________
3. There is another reagent we can use to only induce one equivalent of hydrogen to a carbonyl: _____________
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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CONCEPT: KETONES FROM ACID CHLORIDES
When a good leaving group is present on a carbonyl, organometallics tend to react twice, yielding disubstituted alcohols.
Nucleophilic Acyl Substitution on Esters and Acid Chlorides
From Acid Chlorides:
We can reduce the power of the organometal by using a Gilman to yield _________ from RCOCl
□ This reagent stops after the first nucleophilic addition
ORGANIC - LOUDON 6E
CH. 21 - THE CHEMISTRY OF CARBOXYLIC ACID DERIVATIVES
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PRACTICE: Provide the major product for the following reaction.
Cl
O
(CH3CH2)2CuLi
Ether
ORGANIC - LOUDON 6E
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