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Alcohols

Alcohols. Biological Activity Nomenclature Preparation Reactions. Some Alcohols. Alcohols are Found in Many Natural Products. Paralytic Shellfish Poisoning. Ethanol: the Beverage. Methanol: Not a Beverage. Alcohol Nomenclature. Nomenclature.

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Alcohols

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  1. Alcohols Biological Activity Nomenclature Preparation Reactions

  2. Some Alcohols

  3. Alcohols are Found in Many Natural Products

  4. Paralytic Shellfish Poisoning

  5. Ethanol: the Beverage

  6. Methanol: Not a Beverage

  7. Alcohol Nomenclature

  8. Nomenclature

  9. Oxidation levels of oxygen- halogen- and nitrogen-containing molecules

  10. Acidity of Alcohols • Due to the electronegativity of the O atoms, alcohols are slightly acidic (pKa 16-18). • The anion dervived by the deprotonation of an alcohol is the alkoxide. • Alcohols also react with Na/K (same as water does) to give the alkoxide.

  11. Withdrawing Groups Enhance Acidity alcohol pKa CH3OH 15.54 CH3CH2OH 16.00 CF3CH2OH 12.43 (CH3)3COH 18.00 (CF3)3COH 5.4 Why?

  12. Withdrawing Groups Enhance Acidity alcohol pKa CH3OH 15.54 CH3CH2OH 16.00 CF3CH2OH 12.43 (CH3)3COH 18.00 (CF3)3COH 5.4

  13. A similar case for phenols

  14. Physical Properties CH3CH2CH3 -42 0.08 i CH3OCH3 -25 1.3 ss CH3CH2OH 78 1.7 vs b.p. oC m D sol. in H2O

  15. Intermolecular H-Bonding

  16. Preparation of Alcohols • Reduction of ketones and aldehydes • Reduction of esters and carboxylic acids • Hydration of Alkenes • Nucleophilic addition • Grignard reaction • Acetylide addition • Substitution • Epoxide opening

  17. NaBH4 Reduction

  18. Some Examples

  19. Two Alcohol Products Form in Lab

  20. LiAlH4 Reductiona Stronger Reducing Agent

  21. LiAlH4 is a much stronger reducing agent

  22. NaBH4 is More Selective

  23. Oxymercuration HydrationMarkovnikov

  24. Hydroboration HydrationAnti-Markovnikov

  25. Base Catalyzed Ring-Opening of Epoxides

  26. Acid Catalyzed Ring-OpeningAqueous and in Alcohol

  27. Nucleophilic addition to Carbonyl CompoundsAcetylides

  28. Organometallic ChemistryGrignard Reaction

  29. Grignard Reagents React With Ketones to form tertiary alcohols

  30. Grignard Reagents React With Aldehydes to form secondary alcohols

  31. Grignard Reagents React With Formaldehyde to form primary alcohols

  32. Grignard Reagentsreact (twice) withEstersto form3o Alcohols

  33. Grignard Summary

  34. Grignard Summary

  35. Grignard Reagents are exceptionally strong bases

  36. Synthesis

  37. Retrosynthetic Analysis

  38. 4-Step Synthesis

  39. Synthesize Using Only 1,2, or 3-Carbon Reagents

  40. Retrosynthesis

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