Chapter 21 November 7 - Example: Reaction Mechanism: LiAlH...

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1 Preparation and Reactivity of Acyl Halides Preparation: Previously Encountered Reaction: Friedel­Crafts Acylation
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2 Reactions of Acyl Halides Hydrolysis: Mechanism: React with H 2 O to yield carboxylic acids Generates HX, a mild base is added to neutralize the reaction (pH = 7)
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3 Reactions of Acyl Halides (cont'd) Formation of Esters: Examples: Acid Halides + alcohols with pyridine (or mild NaOH) Less hindered alcohol groups are more reactive (1 o >2 o >3 o ) Allows for selective synthesis when 2 alcohol groups are present The mechanism is identical to hydrolysis. The only difference is the alcohol used:
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4 Reactions of Acyl Halides (cont'd) Aminolysis: Examples: React with NH 3 , 1 o and 2 o amines HCl is neutralized by a second equivalent of amine or an added base
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5 Reactions of Acyl Halides (cont'd) Reduction: Turning Acid Chlorides into Alcohols
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Unformatted text preview: Example: Reaction Mechanism: LiAlH 4 reduces acid halides to aldehydes and then to 1 o alcohols 6 Reactions of Acyl Halides (cont'd) Reductive Alkylation using Grignard Reagents: Examples: Formation of Ketones using Gilman Reagents: Example: Produces a 3 o alcohol and goes through a ketone intermediate that is difficult/impossible to isolate Acid chloride + diorganocopper reagent 7 Preparation of Acid Anhydrides: Example: Reaction Mechanism: Carboxylate + acid chloride Why do you use ether and not H 2 O as the solvent? 8 Reactions of Acid Anhydrides Reaction Summary: Show comparable chemistry to acid halides Slightly less reactive (see chart) 9 Reactions of Acid Anhydrides Preparing Commercially Valuable Acetate Esters Ester Formation: Aminolysis:...
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This note was uploaded on 12/20/2011 for the course CHEM 234-54 taught by Professor Morrison during the Fall '09 term at University of Georgia Athens.

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Chapter 21 November 7 - Example: Reaction Mechanism: LiAlH...

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