ORGANIC CHEMISTRY Chapter ll 11.15 Synthesis of Ethers Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 11.15 Synthesis of Ethers
ORGANIC CHEMISTRY Chapter ll 11. 15A Ethers by Intermolecular Dehydration of Alcohols H R-O-H+ h-o-RR-o-R+ Ho H2SO4 CH3 CH2OCH CH3 140°C CH3 CH2OH H2SO4 180°C CH2-CH2 Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 11.15A Ethers by Intermolecular Dehydration of Alcohols R O H + H O R H+ R O R + H2O CH3CH2OH H2SO4 140°C H2SO4 180°C CH2 CH2 CH3CH2OCH2CH3
ORGANIC CHEMISTRY Chapter ll Mechanism OH2 HOCH2CH CH3CH2OH CH3CH2 2-H2O N CH3 CH2OCH2CH3 CH2CHoOChCH H H2SO, ROR RoH roH roR ho ROR Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 Mechanism Mechanism OH2 SN2 H2O CH3CH2OH H+ CH3CH2 HOCH2CH3 CH3CH2OCH2CH3 H+ CH3CH2OCH2CH3 H ROH + R'OH H2SO4 ROR' ROR R'OR' + H2O
ORGANIC CHEMISTRY Chapter ll 11.15B The Williamson Synthesis of Ethers RONa +R—L ROR NaL AroNa ArOR L=—Br,—I,-OSO2R",-OSO2OR OK OCHoCH cha Br ( CH3)3 CONa CH3I (CH3)3COCH Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 11.15B The Williamson Synthesis of Ethers ROR' ArOR' + RONa ArONa R' L + NaL L = Br, I, OSO2R'' , OSO2OR'' OK + CH3CH2Br OCH2CH3 (CH3)3CONa + CH3I (CH3)3COCH3
ORGANIC CHEMISTRY Chapter ll 11. 15C tert-Butyl Ethers by Alkylation of Alcohols. Protecting groups H2SO4 CH3 tert-Buty RCH,OH CH2=CCH RCH2O-C- CH3 protecting CH CH group HOCH2CH2CH2Br+NaC≡CH→- NaOCHoCH2CHBr +HC≡CH no HOCH2CHCH2-C≡CH Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 11.15C tert-Butyl Ethers by Alkylation of Alcohols. Protecting Groups RCH2OH CH2 CCH3 CH3 + H2SO4 RCH2O C CH3 CH3 CH3 tert-Butyl protecting group HOCH2CH2CH2Br + NaC CH NaOCH2CH2CH2Br + HC CH no HOCH2CH2CH2 C CH
ORGANIC CHEMISTRY Chapter ll CH H2SO4 HOCH, CH,CH, Br CH,=CCH3 BrCH2 CH2 CH2O-C-CH3 CH3 CH CH NaC三CH HO HC=C-CHbCHCH0-C-CH H CH3 CH HC=C-CHCHChOH CH2-C-OH 4-Pentyn-I-ol CH Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 HOCH2CH2CH2Br CH2 CCH3 CH3 + H2SO4 BrCH2CH2CH2O C CH3 CH3 CH3 NaC CH CH2CH2CH2O C CH3 CH3 CH3 HC C H2O H+ HC C CH2CH2CH2OH C CH3 CH3 CH3 + OH 4-Pentyn-1-ol
ORGANIC CHEMISTRY Chapter ll 11. 15D Silyl Ether Protecting Groups CH CH imidazole ROH +C1-Si-C(CH3)3 DMI RO-SI-C(CH3)3 F CH CH tert-Butylchlorodimethylsilane (TBDMSCI (RO-TBDMS) mIdazole HN、/N CH BUNF CH RO-SI-C(CH3)3 ROH F-Si-C(CH3)3 THE CH CH3 Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 11.15D Silyl Ether Protecting Groups ROH Si CH3 C(CH3)3 CH3 + Cl imidazole DMF RO Si CH3 C(CH3)3 CH3 tert-Butylchlorodimethylsilane (TBDMSCl) (RO TBDMS) imidazole HN N RO Si CH3 C(CH3)3 CH3 THF ROH Si CH3 C(CH3)3 CH3 + F Bu4N F
ORGANIC CHEMISTRY Chapter ll 11 16 Reactions of ethers Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 11.16 Reactions of Ethers
ORGANIC CHEMISTRY Chapter ll o The oxygen of ether linkage makes ether basic Ether can react with proton donors to form oxonium salts HBr R-0-R R-0-R H An oxonium salt R R-OR+ BF3 O:BF R R R R O: Mg: O R R R Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 The oxygen of ether linkage makes ether basic. Ether can react with proton donors to form oxonium salts. R O R R O R H HBr An oxonium salt R O R R O R + BF3 R O R Mg R R R O R BF3
ORGANIC CHEMISTRY Chapter ll o Heating dialkyl ethers with very strong acids(hl, hBr and h,sO4) cause tem to undergo reactions in which the carbon-oxygen bond breaks chr CHOCHo CH2+ hBr-chr2 ch Br Chrchooh HBr CHr CH,Br H,O CH3-O-CH3 + HI-CH3oH Ch3I HI CHal (CH3)3C-0-CH3 +HI(CH3)3CI CH3OH 少-0CH+H OH+ CH3I Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 11 Heating dialkyl ethers with very strong acids (HI, HBr, and H2SO4) cause tem to undergo reactions in which the carbon-oxygen bond breaks. CH CH3CH2Br 3CH2OCH2CH3 + HBr + H2O + CH3CH2OH HBr CH3CH2Br CH3 O CH3 + HI CH3OH + CH3I CH3I (CH3)3C O CH3 + HI (CH3)3CI + CH3OH OCH3 + HI OH + CH3I HI
