16.5 Synthesis of ketones 1. Ketones(and aldehydes) by ozonolysis of alkenes R R R R 1.O o+0 2.Zn,H20 R H R Alkenes Ketone Aldehyde
16.5 Synthesis of ketones 1. Ketones (and aldehydes) by Ozonolysis of alkenes R R' R'' H 1. O3 2. Zn, H2O O R R' O R'' H + Alkenes Ketone Aldehyde
2. Ketones from friedel-Crafts Acylations AlCl COR Rcocl + hcl COCI hcl R AlCI COR 3 hcl R
2. Ketones from Friedel-Crafts Acylations + RCOCl AlCl 3 COR + HCl + COCl AlCl 3 C + HCl O + AlCl 3 COR + HCl O R O R O
3. Ketones from Oxidations of secondary alcohols OH H, CrO R cH R—C—R OH H, CrO4 H3C -CH3 H3C—C—cH3
3. Ketones from Oxidations of secondary alcohols R C H OH R' H2 CrO4 R C O R' H3 C C H OH CH3 H2 CrO4 H3 C C O CH3
4. Ketones from Alkynes H Hgso c≡c—+H2O c H2S04 H A vinylic alcohol(烯丙醇) Keto form (Unstable) H H3C—c=c—cH3+H2O H3C—c=c—CH H3C c—cH 3 HoSO H H O A vinylic alcohol(烯丙醇) 2-Butanone (Unstable)
4. Ketones from Alkynes C C + H2O HgSO4 H2SO4 C C H O A vinylic alcohol (烯 丙 醇 ） (Unstable) H C C H O H Keto form H3C C C CH3 + H2O HgSO4 H2 SO4 H3C C C CH3 H O A vinylic alcohol (烯 丙 醇 ） (Unstable) H H3C C C O CH3 H H 2-Butanone
5. Ketones from Lithium Dialkylcuprates(二烷基酮锂) R Culi t rccl R c—R Lithium Acyl chloride dialkylcuprate -78°C c|+(CH3)2CuLi— CH3 Lithium dimethylcuprate Hexyl methyl ketone
5. Ketones from Lithium Dialkylcuprates (二烷基酮锂） R2CuLi + R'CCl O Lithium dialkylcuprate Acyl chloride R' C R O O Cl + (CH3 ) 2CuLi -78 o C O CH3 (81%) Lithium dimethylcuprate Hexyl methyl ketone