1. Biological Chemistry FIRST YEAR ORGANIC CHEMISTRY Lecture Seven Aldehydes & Ketones Convenor : Dr. Fawaz Aldabbagh

2. Aldehydes and Ketones O 1s 2, 2s 2 2p 2 2p 1 2p 1 3 sp 2 orbitals

3.   Most Reactive Group –  electrons + polarisation Useful in Synthesis Names al – aldehydes, one - ketones Methanal (formaldehyde) Ethanal (acetaldehyde) Propanal Pentanal

4. Benzaldehyde trans-Cinnamaldehyde Formalin, 35-40% formadehyde in water Preservative that reacts with proteins causing them to resist decay Coelacanth, “prehistoric fish”

5. Propanone (ACETONE) Butanone Acetophenone Benzophenone 3-Methyl-2-pentanone

6. Carbonyls readily undergo Nucleophilic Attack cis and trans isomers possible - H 2 O ANHYDROUS

7. The reaction is acid-catalysed Equilibrium Reactions Other Condensation Reactions

8. Acid-Catalysed Acetal Formation Reversed with acid and water Acetal is stable under basic conditions

9. Addition of Hydrogen Cyanide Nucleophilic addition reactions

10. Professor Victor Grignard (1912 Nobel Prize) Developed this chemistry with Professor P. A. Barbier

11. Examples 2. H 3 O +

12.  -Hydrogens next to Carbonyl Groups are relatively acidic

13. Keto-Enol Tautomerism The negative charge is delocalised C=O bond stronger than C=C bond so equilibrium lies towards keto-tautomer Enol formation can be acid or base catalysed