第七章醇与醚

第七章醇与醚醇的取代反应醇的消除反应醇的氧化反应醚的合成醚的分解环氧化合物的分解7.1结构与命名1．结构O2s2p不等性sp3杂化sp3ORR(H)键角11002．命名A.醇的命名选择含有羟基的最长的碳链做主链；编号使羟基的号码最小；母体化合物名称为醇其他取代基名称在前。CH3CH=CHCHCH2CHCH3OHCH312345764-甲基-5-庚烯-2-醇OH环己醇OH3-环己烯醇123456B.醚的命名两个烃基名称罗列在母体化合物命称“醚”前，复杂的烃基上联有简单的醚键则称为“烃氧基”作为取代基。CH3OC2H5CH3OCH3OC(CH3)3甲乙醚苯甲醚甲基叔丁基醚O四氢呋喃OO二氧六环CH2-CHCH3OCH2-CHCH2ClO环氧丙烷环氧氯丙烷CH3OCH3C2H5OC2H5O甲醚乙醚二苯醚OOOOOO18-冠醚-67.2物理性质沸点：CH3CH2OCH2CH334CCH3CH2CH2CH2OH118C醇能形成分子间氢键所以沸点高。溶解度：C1~C3的醇与水互溶；C4的醇溶解度~8%。醚类当中，CH3OCH3与水互溶CH3CH2OCH2CH3微溶于水。比重：醇和醚的d1。7.3化学性质I——氢、氧原子的性质1．羟基氢的酸性ROH+MROM+H2M=K、Na、Mg、AlCH3CH2OH+NaCH3CH2ONa+H2(CH3)3COH+K(CH3)3COK+H2CH3CH(OH)CH3+Al((CH3)2CHO)3Al异丙醇铝(i-PrO)3Al2．氧原子的配位性醇与CaCl2和MgCl2等形成配合物：CaCl24C2H5OH；MgCl26C2H5OH，醇不能用CaCl2来干燥。醚可与BF3、RMgX形成配合物：R2OBF3；(R2O)2MgXR，生成Grignard试剂时，醚不仅起到溶剂作用，而且作为配位体稳定Grignard试剂。由于空间阻碍，醚不能与CaCl2和MgCl2等形成配合物，所以，醚可以用CaCl2来干燥。3．酯化反应2CH3OH+HO-S-OHOOCH3O-S-OCH3OO硫酸二甲酯(剧毒)甲基化试剂OHNaOHONaCH3IOCH3(CH3)2SO4HOOHO(CH3)2SO4CH3COCH3CH3OOHO3C2H5OH+POCl3PO(OC2H5)3磷酸三乙酯3C2H5OH+PCl3P(OC2H5)3亚磷酸三乙酯POCl3POOOPOHOHOOHOHClClOOHOOHOOPOOOPOnOONNHHOH(C6H5)2PCl(C2H5)3N,ONNH(C6H5)2POHRCOOH+R'OHRCOOR'+H2OH+CH3COOH+C2H5OHCH3COOHC2H5+H2OH+H+COOH+C2H5OHCOOC2H5+H2O乙酸乙酯沸点低，蒸除酯推移平衡。苯甲酸乙酯沸点高，分出水推移平衡。7.4化学性质II——将-OH转化为-X1.与HX反应活性：HClHBrHICH3CH2CH2CH2OH+HBrCH3CH2CH2CH2Br+H2O机理：CC3H7DHOHH-BrCC3H7DHOH2质子化BrBrCC3H7HOH2DCC3H7DHBr类似SN2机理机理：醇OH发生取代反应的活性顺序：OHHBrBrCH3CCH2OHCH3CH3HBrCH3CCH2CH3CH3BrCH3CCH2OHCH3CH3HBrCH3CCH2OH2CH3CH3质子化CH3CCH2CH3CH3CH3CCH2CH3CH3BrT.M.醇的OH比卤代烃中的X更容易发生消除反应。phCH2OHCH2=CHCH2OH302010CH3OH醇与HX反应时的邻位基团效应当-OH的邻位有亲核性基团(-X、-OH、-OR、-SH、-SR、-ph等)的时候，醇与HX反应时产物发生外消旋化，称为邻位基团效应。C2H5CH3BrOHHHHBrC2H5CH3BrBrHH(DL)C2H5CH3BrOHHHHBrC2H5CH3BrBrHH(DL)机理：C2H5CH3BrOHHHC2H5OHHHCH3BrC2H5HCH3BrHHOH-BrC2H5CH3BrHH2OH-H2OC2H5CH3BrHHC2H5CH3BrHHBrabaC2H5CH3BrHHBrC2H5CH3BrBrHHbC2H5CH3BrHHBrC2H5CH3BrBrHH对映体C2H5CH3BrOHHHC2H5OHHHCH3BrC2H5HCH3BrHHOH-BrC2H5CH3BrHH2OH-H2OC2H5CH3BrHHC2H5CH3BrHHBraaC2H5CH3BrHHBrC2H5CH3BrBrHHbC2H5CH3BrHHBrC2H5CH3BrBrHH对映体直链伯醇不重排，类似SN2反应机理；其它醇重排，并且有邻位基团效应。HOBrHHH-BrBrHHBr(DL)CH2CHCH3OHHBrCHCH2CH3Br(DL)2.与PX3反应ROH+PCl3RCl+H3PO3POCl3RCl+H3PO4PBr3RBr+H3PO3特点：不重排；缺点：生成的磷酸、亚磷酸难以分离。P+I2RI+H3PO3CH3-C-OHCH3CH3PBr2CH3-C-BrCH3CH3CH3(CH2)11OHPBr3CH3(CH2)11BrLocus试剂——ZnCl2/HCl：鉴别醇的级别ROH+HClRCl+H2OZnCl2醇的比重1；相应卤代烃的比重1，观察浮在上层的醇沉入下层的时间即可判断醇的级别：phCH2OHCH2=CHCH2OH302010很快很慢，且需加热。3．与SOCl2反应机理：ROH+Cl-S-ClRCl+SO2+HClO二氯亚砜b.p.780CCphOHHDSClClOCphOHDSClClOH-HClCphODSClOH氯代亚硫酸酯内返CphHDCl构型保持-SO2如果在上述反应体系中加入吡啶，在生成氯代亚硫酸酯后，进一步生成吡啶盐，那么反应机理变为：SOCl2直接氯代，构型保持；加入吡啶，构型翻转CphOHHDSClClOCphOHDSClClOH-HClCphODSClOH氯代亚硫酸酯NCphODSONHClCphHDCl构型翻转COOHHOOHOHCH3OHSOCl2COOCH3HOOHOHSOCl2(R=CH3(CH2)11)CH2OHROORORTHF,DMF(R=CH3(CH2)11)CH2ClROORORLawesson试剂——将-OH转化为-SH；将C=O转化为C=SSPSPCH3OOCH3SSLawesson试剂：OCH3OLawesson试剂OCH3S7.5化学性质III——消除与重排1．消除反应A.分子内脱水CH3CH2OHH2SO41700CCH2=CH2+H2OCH3CH2CH2CH2OH75%H2SO41700CCH3CH2CH=CH2+H2OCH3CH=CHCH3+H2O次产物主产物CH3CH2CHCH360%H2SO41000CCH3CH=CHCH3+H2OOHCH3-C-OHCH3CH320%H2SO4900CCH3-C=CH2CH3B.分子间脱水HOCH2CH2CHCH2OHH3PO4O+H2OCH3CH2OHH2SO41400CCH3CH2OCH2CH3+H2O分子间脱水指断裂C-OH和另一个分子的O-H键生成水。CH3CH2CH2CH2OH75%H2SO41400CC4H9OC4H9+H2O分子间脱水比分子内脱水容易，是因为O-H的键能比C-H键能小，脱水更为容易。C.脱水伴随正碳离子重排H2SO4CH3-CCH-CH3CH3CH3OHC=CCH3CH3CH3CH3CH3-CCH-CH3CH3CH3OH机理：H+CH3-CCH-CH3CH3CH3OH2-H2OCH3-CCH-CH3CH3CH3CH3-CC-CH3CH3CH3HC=CCH3CH3CH3CH3-H+H2SO4OH机理：H+-H2OOHOH2CH2H-H+T.M.2．pinacol重排a.生成稳定的正碳离子；b.基团迁移：-Ar-R；c.迁移的立体化学：反式共平面。CH3CCH3O2MgHgCl2CH3CCCH3CH3CH3OHOH频那醇H+CH3CCCH3CH3CH3O频那酮频那醇重排ph-CC-CH3phCH3OHOHH+ph-CC-CH3phCH3OHOH2-H2O生成稳定的正碳离子ph-CC-CH3phCH3OHph-CC-CH3phCH3OHph-CC-CH3phCH3OH-H+ph-CC-CH3phCH3Oph-CC-CH3phCH3OHOHH+ph-CC-CH3phCH3OHOH2-H2Oph-CC-phCH3OHCH3迁移：-Ar-Rph-CC-CH3phCH3OHph-CC-CH3phCH3OH-H+ph-CC-CH3phCH3OH+CH3HOHOHH+CH3HOHOHH+CH3HOHOH-H2OCH3HOHOH2-H2OCH3HOHOH2-H2OCH3HOHOH2OH-H+HCH3-H+OHCH3H-H+CH3HOHOHCH3OCH3HCH3CHO1.RCOOOH2.H3+OOHOHOHOHH+O冷KMnO4OHOHH+OHHOOH+OO2MgHgCl2OHHO-卤代醇在Ag+存在下重排-氨基醇在HNO2存在下重排以上三种重排统称为pinacol重排CH3-CC-CH3phCH3XOHAg+CH3-CC-CH3phCH3OH在-X处生成正碳离子-AgXCH3-CC-CH3phCH3OHCH3-CC-CH3phCH3OH-H+CH3-CC-CH3phCH3O7.6化学性质IV——醇的氧化与合成1．醇的氧化A．HNO3——氧化醇及环醇开环成酸ClCH2CH2CH2OHClCH2CH2COOHHNO3HNO3OHHOOC(CH2)4COOHOHNO3B．KMnO4/H+和K2Cr2O7/H+——氧化醇成酸(酮)RCH2OHKMnO4H+K2Cr2O7H+或RCOOHR1CHR2KMnO4H+K2Cr2O7H+或OHR1-C-R2O10醇氧化生成酸20醇氧化生成酮CH3-C-OHCH3CH3KMnO4H+K2Cr2O7H+或CH3C=CH2CH3[]30醇先脱水生成烯烃，烯烃再被氧化KMnO4H+K2Cr2O7H+或CH3CCH3O+CO2+H2O催化氧化法代替上述的氧化剂法，即用Co(OAc)2为催化剂，以空气中的氧气为氧化剂来实现上述氧化OHKMnO4H+OOHKMnO4H+OCOOHCOOHCo(OAc)2O2CH3(CH2)5OHCH3(CH2)4COOHC．CrO3/稀H2SO4和CrO3/吡啶Jones试剂和Sarrett试剂——氧化醇成醛(酮)RCH2OHCrO3稀H2SO4RCHOR1CHR2OHR1-C-R2OCrO3NCrO3稀H2SO4CrO3N10醇氧化生成醛20醇氧化生成酮CH2=CHCH2CH2CHCH3OHCH2=CHCH2CH2CH2CH2OHC2H5OOCCH2CHCOOC2H5OHCrO3NCrO3稀H2SO4CH2=CHCH2CH2CCH3OCH2=CHCH2CH2CH2CHOC2H5OOCCH2CCOOC2H5OOHOOHOHCrO3NOHOOHHOCH3OCH2OOHMnO2CH2Cl2,室温CH3OCH2OHOD．新制MnO2——氧化烯丙基位的羟基OOOHHO新制MnO2HOCH2CH=CHCHCH2CH2CH2OHOH新制MnO2H-CCH=CHCCH2CH2CH2OHOOE．Al(i-PrO)3/CH3COCH3——氧化仲醇成酮CH2CHCH3OHOHAl(i-PrO)3CH3COCH3Al(i-PrO)3CH3COCH3CH2CCH3OOAl(i-PrO)3i-PrOHAl(i-PrO)3i-PrOHF.DMSO、(COCl)2——氧化醇成醛(酮)OHOH(CH3)3C-Si-ClCH3CH3OHOTBDMSTBDMS=(CH3)3C-Si-CH3CH3保护10醇的-OHOOTBDMSO=C-ClO=C-ClDMSO,(C2H5)3N低温OHOH(COCl)2D