Carboxylic Acids and Derivatives. Decarboxylation R H + CO 2. R OH Reaction type: Elimination. H H Malonic acid. Mechanism:

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1 rganic hemistry arboxylic Acids and Derivatives Decarboxylation eaction type: Elimination 2 Malonic acid Mechanism: 235

2 rganic hemistry arboxylic Acids and Derivatives ucleophilic Acyl Substitution u Two events in a nucleophilic acyl substitution reaction: u In nucleophilic substitution (e.g. for alkyl halides) the nucleophile cannot attack until the leaving group leaves, why is there a difference? ucleophilic Acyl Substitution : eactive Systems ucleophile: Electrophile: u u ucleophilic Acyl Substitution : Less eactive ucleophile: Electrophile: Activate the ucleophile: Activate the Electrophile: u B u B u B 236

3 rganic hemistry arboxylic Acids and Derivatives Interconversion eactions of Acyl hlorides: Acid anhydrides Esters Acids ' ' 2 " l l l BASE ' " l ' l Amides 2 l l 2 eaction type: Friedel-rafts Acylation of Benzene All 3 l l eaction type: eagent : Limitation: 237

4 rganic hemistry arboxylic Acids and Derivatives Interconversion eactions of Acid Anhydrides Esters ' ' ' Acids 2 ' Amide 2 ' 2 eaction type: Interconversion eactions of Esters Esters Acids Amides ' 2 2 eaction type: Transesterification: ydrolysis: Amide preparation: BASI conditions: AIDI conditions: " or - " then l BASE " ' " " 2 238

5 eduction of Esters rganic hemistry arboxylic Acids and Derivatives LiAl 4 ' ' eactions usually in Et 2 or TF followed by 3 work-ups eaction type: verall eaction: eagents: Mechanism: Li 3 Al Li 3 Al eactions of Li and MgX with Esters 2 Li" or 2 MgBr" ' ' eaction usually in Et 2 followed by 3 work-up eaction type: 239

6 rganic hemistry arboxylic Acids and Derivatives ucleophilic Addition to itriles u eaction type: Strong nucleophiles: u Weak nucleophiles: Further reaction 240

7 ydrolysis of itriles rganic hemistry arboxylic Acids and Derivatives eaction type: Mechanism: Strong Acid or Base 2 EAT 2 EAT AMIDE

8 eduction of itriles rganic hemistry arboxylic Acids and Derivatives LiAl eactions usually in Et 2 or TF followed by 3 work-up eaction type: Products: eagents: eactions of Li or MgX with itriles ' 1) Li or MgX 2) 3 ' eaction usually in Et 2 or TF eaction type: Products: MgX 2) 3 ' 1) Li or MgX ' itriles are less reactive than aldehydes and ketones. Why doesn t the Grignard reagent continue to react at the ketone stage? ' 242

9 eactions of Amides ydrolysis of Amides rganic hemistry arboxylic Acids and Derivatives ' 2 eaction type: Strong acid or base heat ' 2 eagents: Mechanism basic: 2 2 Mechanism acidic:

10 eduction of Amides rganic hemistry arboxylic Acids and Derivatives LiAl eactions usually in Et 2 or TF followed by 3 work-ups eaction type: Products: eagents: Primary amine Secondary amine Tertiary amine 2 LiAl 4 LiAl 4 2 LiAl Mechanism: Li Al 3 Al Why do we get the amine rather than the alkane? Li Li Al

11 Spectroscopy arboxylic Acids Acyl alides Anhydrides Esters Amides I = - rganic hemistry arboxylic Acids and Derivatives 1 M = 13 M UV-VIS itriles 245

12 Mass Spec arboxylic Acids Acyl alides rganic hemistry arboxylic Acids and Derivatives Acid Anhydrides Esters acylium ions Amides itriles 246