1. Ketones, Aldehydes CH21 PS CLASS

2. Recall the many times we’ve synthesized these! I command thee. Oxidation of R-OH – (Periodinane, CrO 3 /Na 2 Cr 2 O 7 ) Hydration of Alkynes (keto-enol tautomerism) – H 3 O+/HgSO 4, BH 3 /H 2 O 2, OH-, etc… Friedel-Crafts ACYLation of Aromatics – (acid halide + AlCl 3 )

3. REACTIONS OF ALDEHYDES/KETONES Oxidation of Aldehydes Nucleophilic Additions (overview) – Hydride (H-) and Grignard (R-) as Nucleophiles – Water addition (hydrate/diol/geminal diol formation) – Alcohol addition (acetal formation) – Amine addition (imine formation) Conjugate Nucleophilic Addition Reactions

4. Major Synthesis

11. Oxidation of Aldehydes Where [O] = CrO 3 among others.

12. Nucleophilic Addition Rxns Slightly different mechanisms in acid or base. Neutral vs. Negatively charged Nucleophile General picture (basic):

13. Reactivity Notes: Less steric hindrance with aldehyde Benzaldehyde less reactive due to resonance stabilization.

14. Reduction of Ketones/Aldehydes

15. Addition of Grignard Reagent

16. Grignard Reagents + carbonyls

17. Practice! COME UP WITH PAIRS, More than one answer for some.

18. Practice!

19. Hydrate formation/ Geminal Diols

20. Basic vs. Acidic BASIC: Strong nucleophile attacks, as in Nu- ACIDIC: Carbonyl is converted to a stronger ELECTROPHILE as CABON BECOMES MORE POSITIVE.

21. Problem

22. Acetal formation ACID CATALYZED… AGAIN, CARBONYL MADE INTO BETTER ELECTROPHILE.

23. Acetal Formation

24. 2 alcohols/ 1 diol can be used to ‘protect’ an aldehyde or ketone from a reaction.

25. Nuc. Addition of Amines to form: Imines Amine must have 2 protons, RNH 2

28. If amine is 2° we form enamines

31. Practice addition of amines:

33. Problems Predict the Products!

34. Problems

35. Wittig reaction, addition of R: - to C=O forming C=C Limits of SN2???

36. Addition of ylides

37. Exercises

39. Conjugate Nucleophilic Addition Rxns

40. THE DOUBLE BOND IS EFFECTIVELY “POLARIZED” INTO A NEGATIVE REGION THAT’S RESONANCE STABILIZED, AND A POSITIVE REGION AT THE BETA-CARBON.

41. Predict the product + HCN

42. Practice

43. Predict the Products a.NaBH 4 /H 3 O+ b.NH 2 OH/HCl c.2 CH 3 OH /acid d.CH 3 MgBr then acid

44. Predict the Products NaBH 4 /H 3 O+ NH 2 OH/HCl 2 CH 3 OH /acidCH 3 MgBr then acid

45. Predict the Products NaBH 4 /H 3 O+ NH 2 OH/HCl 2 CH 3 OH /acidCH 3 MgBr then acid

46. Exercises