2.断裂RO-H的反应1).与活泼金属的反应Mg →(RO)2MgROH +Na → RONa→AI(OR)3AL相对酸性:H,O>ROH>HC三CR>NH,>RH醇的相对酸性:MeOH> EtOH >(CH3),CHOH> (CH3)3C-OH1915pKa2).酯化反应:HNO3 -→ RONO2H2SO4→ROSO2OH与无机酸ROHPOCl3 → (RO)P=O的酯化:CISO2<)CH3 -→ ROSO)-CH3
2. 断裂RO-H的反应 1).与活泼金属的反应 相对酸性:H2O > ROH > HC三CR > NH3 > RH 醇的相对酸性:MeOH > EtOH > (CH3 )2CHOH > (CH3 )3C-OH pKa 15 19 2).酯化反应: 与无机酸 的酯化: ROH + Mg Na Al (RO) 2Mg RONa Al(OR) 3 ROH + HNO3 H2 SO4 POCl 3 ClSO2 RONO2 ROSO2OH (RO) 3 P=O CH3 ROSO2 CH3
与有机酸的酯化H*ROH + R'COOHR'COOR + H,O3.脱水消除反应H,SO41).分子内脱水CH3CH20HCH,=CH2190°C反应活性:3°>2°>1°(大多为E1历程,因为H,0+易离去)2).分子间脱水:H,SO4EtOEt2CH,CH,0H140°C
与有机酸的酯化: 3.脱水——消除反应 1).分子内脱水: 反应活性:3º> 2º > 1º (大多为E1历程,因为H2O+易离去) 2).分子间脱水: CH3 CH2 OH CH2 CH2 H2 SO4 190C 2CH3 CH2 OH H2 SO4 140C EtOEt ROH + R'COOH R'COOR + H2 O H
消去的取向:(查依采夫规则)H,SO4CH,CH,-CH-CHCH,CH=CHCH,+ CH3CH,CH=CH,86°COH80%20%也有重排(E1历程)CH3CH3H3CCH3H+CH3:CCH-CH3CH3:CCH=CH2心十CH3CH,OHHCCH370%30%
消去的取向:(查依采夫规则) 也有重排(E1历程) CH3 CH2 CH OH CH3 H2 SO4 86C CH3 CH CHCH3 + CH3 CH2 CH CH2 80% 20% CH3 C CH3 CH3 CH OH CH3 C C H3 C H3 C CH3 CH3 H+ CH3 C CH3 CH3 + CH CH2 70% 30%
4.醇的氧化脱氢反应K,CrO-氧化:10RCH,OHRCHO →RCOOHH+OH0K,Cr0-i2°R-CR'R-CH-R'H+3°一般不反应,条件激烈时,氧化同时裂解:CH3HCH+C=CHCH3:C-OH + HNO3--H,0HCCH3[0][0]-CH3-C-CH3 +H,O + CO2CO, + H,O + CH3COOH
4. 醇的氧化脱氢反应: 氧化: 3º 一般不反应, 条件激烈时,氧化同时裂解: 1º 2º RCH2OH H + K2CrO7 RCHO RCOOH R CH OH R' H + K2CrO7 R C O R' CH3 C CH3 CH3 OH H+ C CH H3C H3C [O] CH3 C O CH3 + H2O + CO2 [O] CH3COOH -H2O + HNO3 CO2 + H2O +
[O]选择性氧化:RCH,OHRCHO例:SarrettCH=CH-CH,CH,OHCH=CH-CH,CHO1新制MnO2CHCH-CH20HCHCH-CHO25°COH0OHoppenauerCH2=CH-C—CH3 + CH3-C-CH3CH2=CH-CH-CH3丙酮JonesJones试剂=CrO,+烯H,SOHORCH,OHRCHO +H,脱氢:CuRRCCHOH325°CC=0 + H2RR
选择性氧化: 例: ① ② Jones试剂=CrO3+烯H2SO4 脱氢: HO Jones O RCH2OH R CHOH R' Cu 325C RCHO +H2 R C R' O + H2 RCH2 OH RCHO [O] CH2 CH CH2 CH2 OH Sarrett CH2 CH CH2 CHO CH2 CH CH2OH CH2 CH CHO 新制MnO2 25C CH2 CH CH OH CH3 oppenauer CH2 CH C O CH3 + CH3 C H OH CH3 丙酮