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A Review of “Organic Chemistry” in First Term

A Review of “Organic Chemistry” in First Term. Part A Some Important Concepts and Structure. 1. Different kinds of Organic Compounds. Alkanes Cycloalkanes Alkyl halides Alcohols. Saturated Compd. Hybrization Geometric structure. C atoms. Alkenes Alkynes Diene Arenes.

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A Review of “Organic Chemistry” in First Term

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  1. A Review of “Organic Chemistry” in First Term Part A Some Important Concepts and Structure 1. Different kinds of Organic Compounds. Alkanes Cycloalkanes Alkyl halides Alcohols Saturated Compd. Hybrization Geometric structure C atoms Alkenes Alkynes Diene Arenes Unsaturated Compd. Alkyl Allylic Benzyl Reactive intermediates Carbocations Radicals

  2. Triple bonds 2. Formation of Chemical bonds. Stereoisomers Configurational isomers Enatiomers(R,S) Diatereomers Meso-isomers Racemic mixture C–C σbond C–Hσbond C=C double bonds cis-trans Isomers: (Z),(E) Structure Optical activity Chiral Achiral Reso- nace form Mole. Optical Symetric Unsymetric 3. Bilingual nomenclature. Symetric elements Constitutional Stereoisomers Conformers Newman Fischer 4. Isomers Projections 5. Aromaticity Chair conformation

  3. 6. Organic acids and bases 7. Substitutent effects Problem 1 The structure of Comp. A is represented by the constitution shown: (a) How many of the optical isomers? (b) Write the Fischer projections of the optical isomers and give the IUPAC names. (c) Sight down the C3–C4 bond, and draw the most stable Newman projection formulas of the optical isomers . (d) Identify the relationship of these optical isomers.

  4. Problem 2 Write a structural formula for the most stable conformation of the each of the following compounds: (a) cis-Cyclohexadiol. (b) trans-4-tert-Butyl-1-methylcyclohexane. (c) Give the stable conformer.

  5. I- TSCl or MsCl Part B. Organic Reactions • Halogenation of alkanes. • α- Halogenation of alkenes. • Reactions of NBS. • Radical • Reactions d. Anti-Markovnikov addition: (HBr–ROOR) Substrates Nucleophile a. Alkyl halides 2. Nucleophilic Substitutions b. Alcohols: HX, PX3, SOCl2 ROTs

  6. 3. Elimination Substrates Electrophiles HX, X2, X2+H2O, H+/H2O (HgSO4/H2SO4/H2O) B2H6/H2O2–OH -, Alkenes Alkynes 4. Electrophilic additons 1,2-adddition 1,4-addition cycloaddition Conjugated dienes Halogenation Nitration Sufonation Friedel-Crafts reactions 5. Aromatic Electrophilic substitutions

  7. H2 Pd,Ni… H2 Lindlar-Pd or P-2 Catalyst Na or Li Liq. NH3 Na2Cr2O7/H+ H2 / Pd,Ni… Alkenes Dienes Alkanes 6. Hydrogenations cis-Alkenes Alkynes trans-Alkenes Alkenes Aldehydes or Ketones 7. Oxidations Carboxyl Acids Alkynes Benzoic acid Alkylbenzens:

  8. Part C. Organic Synthesis • The transformation of • functional groups Organic Synthesis b. The change of C skeleton c. The shift of functional groups Part D. Mechanism of Organic Reactions SN1 Reactions E1 Reactions Rearrange- ment • The formation of • a carbocation Addition of HX to alkenes Aromatic Electrophilic substitution b. The halonium ion: Addition of X2 to a alkene

  9. CH3X RCH2X R2CHX R3CX Methyl 1° 2° 3° Bimolecular reactionly SN1/E1 or E2 SN2 Reactions E2 Reactions c. Bimolecular Reactions Transition States Table 1 Over summary of SN1,SN2, E1 and E2 reactions In solvolysis give SN1/E1,and at low temperature SN1 is favored and gaves mainly E2 with stronger bases(e.g.,RO -) Gaves mainly SN2, with weak base (e.g.,I-,CN-, N3-,RCO2-) and mainly E2 With stronger bases(e.g.,RO-) Gaves mainly SN2, except with a hind- ered-strong base [e.g.,(CH3)3CO-] and then gives mainly E2 Gives SN2 reac- tions

  10. Part E. Stereoselectivity of Reactions 1. Catalytic hydrogenations of alkynes: H2 / Lindlar-Pd Syn-addition P-2 catalyst Anti-addition Li or Na / Liq. NH3: 2. Addition of X2 to Alkenes: Anti-addition 3. Hydroboration-Oxidation of alkenes: Syn-addition Syn-addition 4. Epoxidation of Alkenes: Inversion of configuration 5. SN2 Reactions: Retention of configuration SN1 reaction: racemization Anti-Elimination 6. E2 Reaction:

  11. Part F. Regioselectivity of Reactions 1. Electrophilic addiitons of alkenes: Markovnikov’s rule 2. Addition of HBr to a alkene in the presence of ROOR: Anti-Markovnikov’s rule 3. Elimination: Zaitsev’s rule 4. Aromatic electrophilic substitution of substituted benzenes: Directing effect of substituents on aromatic ring

  12. Part G. Identification of Organic Compounds 1. Ozonolysis of alkenes and alkynes. 2. Oxidations of Alkenes by KMnO4. 3. Additions of Br2 to Alkenes. 4. Reactions of Terminal alkynes with Ag(NH3)NO3 or Cu(NH3)Cl. 5. Reactions of conjugated dienes with maleic anhydride. 6. Oxidations of alkylbenzenes to benzoic acid ……

  13. 1. 2. Isobutyl iodide tert-Butyl chloride

  14. (S)-sec-Butyl azide (R)-sec-Butyl alcohol 3. Racemization SN2 Reaction (S)- (R)- (R)-

  15. Problems to Chapter 8 P246 7.22 (d) 1-Bromo-2-ethylpentane 2- 乙基-1-溴戊烷 3-Bromomethylhexane 7.29 (a) SN2 Rate < p-π conjugation Electronic effect (c) also.

  16. 7.32 SN1: 7.30 (c) (f) Steric hindrance SN2: crowding

  17. (b) (c) 7.34 (a) SN2

  18. 7.35 Ch.P196 SN1 Inversion Retention Racemic-forms

  19. 7.48 (a) (b) 7.49 E1 SN1 E2

  20. 7.50 7.51 (a) (b) (Z)-2,3-Diphenyl-2-butene

  21. 7.52 (2R,3S)-2-Bromo-3-phenylbutane 7.55 (Z)-2-Phenyl-2-butene 7.53(E) SN1

  22. 7.58 A You should comprehend well the meaning of the following reactions : 1.Hydroboration-Oxidation of alkenes. 2. Diels-Alder Cycloaddition Reaction. 3. Friedel-Crafts Alkylation of Arene. 4．SN2 Reaction. 5．The Williamson Synthesis of Ethers.

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