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CHE-302 Review

CHE-302 Review

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CHE-302 Review

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  1. CHE-302 Review

  2. Nomenclature Syntheses Reactions Mechanisms Spectroscopy

  3. Aromatic Hydrocarbons (Electrophilic Aromatic Substitution) Spectroscopy (infrared & H-nmr) Arenes Aldehydes & Ketones Carboxylic Acids Functional Derivatives of Carboxylic Acids Acid Chlorides, Anhydrides, Amides, Esters Carbanions Amines & Diazonium Salts Phenols

  4. Mechanisms: Electrophilic Aromatic Substitution Nitration Sulfonation Halogenation Friedel-Crafts Alkylation & Acylation Nucleophilic Addition to Carbonyl Nucleophilic Addition to Carbonyl, Acid Catalyzed Nucleophilic Acyl Substitution Nucleophilic Acyl Substitution, Acid Catalyzed

  5. Aromatic Hydrocarbons hydrocarbons aliphaticaromatic alkanesalkenesalkynes

  6. Aliphatic compounds: open-chain compounds and ring compounds that are chemically similar to open-chain compounds. Alkanes, alkenes, alkynes, dienes, alicyclics, etc. Aromatic compounds: unsaturated ring compounds that are far more stable than they should be and resist the addition reactions typical of unsaturated aliphatic compounds. Benzene and related compounds.

  7. Nomenclature for benzene: monosubstituted benzenes: Special names:

  8. Electrophilic Aromatic Substitution (Aromatic compounds) • Ar-H = aromatic compound • 1. Nitration • Ar-H + HNO3, H2SO4 Ar-NO2 + H2O • Sulfonation • Ar-H + H2SO4, SO3 Ar-SO3H + H2O • Halogenation • Ar-H + X2, Fe  Ar-X + HX • Friedel-Crafts alkylation • Ar-H + R-X, AlCl3 Ar-R + HX

  9. Friedel-Crafts alkylation (variations) • Ar-H + R-X, AlCl3 Ar-R + HX • Ar-H + R-OH, H+ Ar-R + H2O • c) Ar-H + Alkene, H+ Ar-R

  10. Common substituent groups and their effect on EAS: -NH2, -NHR, -NR2 -OH -OR -NHCOCH3 -C6H5 -R -H -X -CHO, -COR -SO3H -COOH, -COOR -CN -NR3+ -NO2 ortho/para directors increasing reactivity meta directors

  11. If there is more than one group on the benzene ring: • The group that is more activating (higher on “the list”) will direct the next substitution. • You will get little or no substitution between groups that are meta- to each other.

  12. “Generic” Electrophilic Aromatic Substitution mechanism:

  13. Mechanism for nitration:

  14. Mechanism for sulfonation:

  15. Mechanism for halogenation:

  16. Mechanism for Friedel-Crafts alkylation:

  17. Mechanism for Friedel-Crafts with an alcohol & acid

  18. Mechanism for Friedel-Crafts with alkene & acid: electrophile in Friedel-Crafts alkylation = carbocation

  19. Arenes alkylbenzenes alkenylbenzenes alkynylbenzenes etc.

  20. Alkylbenzenes, nomenclature: Special names

  21. others named as “alkylbenzenes”:

  22. Use of phenyl C6H5- = “phenyl” do not confuse phenyl (C6H5-) with benzyl (C6H5CH2-)

  23. Alkenylbenzenes, nomenclature:

  24. Alkylbenzenes, syntheses: • Friedel-Crafts alkylation • Modification of a side chain: • a) addition of hydrogen to an alkene • b) reduction of an alkylhalide • i) hydrolysis of Grignard reagent • ii) active metal and acid • c) Corey-House synthesis

  25. Alkynylbenzenes, nomenclature:

  26. Friedel-Crafts alkylation

  27. Friedel-Crafts limitations: • Polyalkylation • Possible rearrangement • R-X cannot be Ar-X • NR when the benzene ring is less reactive than bromobenzene • NR with -NH2, -NHR, -NR2 groups

  28. Modification of side chain:

  29. Alkylbenzenes, reactions: • Reduction • Oxidation • EAS • a) nitration • b) sulfonation • c) halogenation • d) Friedel-Crafts alkylation • Side chain • free radical halogenation

  30. Alkylbenzenes, EAS -R is electron releasing. Activates to EAS and directs ortho/para

  31. Alkylbenzenes, free radical halogenation in side chain: Benzyl free radical

  32. Alkenylbenzenes, syntheses: • Modification of side chain: • a) dehydrohalogenation of alkyl halide • b) dehydration of alcohol • c) dehalogenation of vicinal dihalide • d) reduction of alkyne • (2. Friedel-Crafts alkylation)

  33. Alkenylbenzenes, synthesis modification of side chain

  34. Alkenylbenzenes, reactions: • Reduction • Oxidation • EAS • Side chain • a) add’n of H2 j) oxymercuration • b) add’n of X2 k) hydroboration • c) add’n of HX l) addition of free rad. • d) add’n of H2SO4 m) add’n of carbenes • e) add’n of H2O n) epoxidation • f) add’n of X2 & H2O o) hydroxylation • g) dimerization p) allylic halogenation • h) alkylation q) ozonolysis • i) dimerization r) vigorous oxidation

  35. Alkenylbenzenes, reactions: reduction

  36. Alkenylbenzenes, reactionsoxidation

  37. Alkenylbenzenes, reactionsEAS?

  38. 100 syn-oxidation; make a model!

  39. Alkynylbenzenes, syntheses: Dehydrohalogenation of vicinal dihalides

  40. Alkynylbenzenes, reactions: • Reduction • Oxidation • EAS • Side chain • a) reduction e) as acids • b) add’n of X2 f) with Ag+ • c) add’n of HX g) oxidation • d) add’n of H2O, H+

  41. Alkynylbenzenes, reactions: reduction Anti- Syn-

  42. Alkynylbenzenes, reactions: oxidation

  43. Alkynylbenzenes, reactionsEAS?

  44. Alkynylbenzenes, reactions: side chain:

  45. Aldehydes and Ketones