1 Chapter 19: More about Oxidation-Reduction Reactions Learning Objectives: 1. Be able to predict products from reductions. 2. Be able to predict products from oxidation of alcohol, aldehydes, ketones, and alkenes. 3. Be able to predict products from hydroxylation of alkenes along with the associated stereochemistry. 4. Be able to predict products from oxidative cleavage of 1,2-diols, alkenes, and alkynes. 5. Be able to write the general electron-pushing (arrow-pushing) mechanisms of ozonlysis and Baeyer-Villiger reaction. 6. Be able to employ the reactions taught in Chem2310 and Chem2320 for multiple step synthesis and functional group interconversion. Sections: 19.1 Reduction Reactions* 19.2 Oxidation of Alcohols* 19.3 Oxidation of Aldehydes and Ketones* 19.4 Designig a Synthesis VIII: Controlling Stereochemistry# 19.5 Hydroxylation of Alkenes 19.6 Oxidative Cleavage of 1,2-Diols 19.7 Oxidative Cleavage of Alkenes 19.8 Oxidative Cleavage of Alkynes# 19.9 Designing a Synthesis IX: Functional Group Interconversion * Sections that will be focused # Sections that will be skipped Recommended additional problems 19.30 – 19.37, 19.39 – 19.49, 19.56 – 19.612 Class Note 19.1 Reduction Reactions* A. H2Pd, Pt, or NiH2Pd, Pt, or Ni B. H2, Pd/CquinolineLindlarcatalyst C. OH2Raney NiHOH2Raney Ni D. LindlarcatalystClO E. HNH2Pd/C3 F. Na or LiNH3 (liq.) G. OHO1) NaBH42) H3O+1) NaBH42) H3O+OCH2CH3ONHCH2CH3O1) NaBH42) H3O+1) NaBH42) H3O+ H. 1) LiAlH42) H3O+OHOOCH2CH3ONHCH2CH3O1) LiAlH42) H3O+1) LiAlH42) H3O+1) LiAlH42) H3O+4 I. H2Raney Ni1) NaBH42) H3O+1) LiAlH42) H3O+OOOCH3?OOH 19.2 Oxidation of Alcohols* and 19.3 Oxidation of Aldehydes and Ketones* A. OHOHCrO3H2SO4Na2Cr2O7H2SO4H2CrO4OH5 B. OOCrO3H2SO4Na2Cr2O7H2SO4 C. OHPCC D. Swern oxidation OH(COCl)2CH3SOCH3(DMSO)6 E. Baeyer-Villiger oxidation (i) CH2CH3RCO3HOCH2CH3RCO3HO (ii) Mechanism (iii) Relative migration tendency H > 3° alkyl > 2° alkyl > 1° alkyl > methyl7 19.4 Designig a Synthesis VIII: Controlling Stereochemistry A. Oxidation of Alkenes with Peroxyacids RRCO3H+ B. Example8 19.5 Hydroxylation of Alkenes and 19.6 Oxidative Cleavage of 1,2-Diols A. 1) OsO4, H2O22) H2O B. CH3OHOHHIO49 19.7 Oxidative Cleavage of Alkenes A. Ozonolysis 1) O3, -78oC2) work-up B. Mechanism of the first step C. Examples (i) 1) O3, -78oC2) Zn1) O3, -78oC2) H2O210 (ii) 1) O3, -78oC2) Zn1) O3, -78oC2) (CH3)2S (iii) 1) O3, -78oC2) (CH3)2S1) O3, -78oC2) H2O211 19.9 Designing a Synthesis IX: Functional Group Interconversion A. synthesisfrom B.
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