有机化学第十一章醛与酮课件.ppt

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1、Aldehyde醛醛Ketone酮酮Carbonyl羰基羰基11 命名命名一、醛一、醛Rule:选主链选主链,定母体；编号；排序定母体；编号；排序甲醛甲醛 methanalformaldehyde乙醛乙醛 ethanalacetaldehyde4-甲基甲基-2-乙基戊醛乙基戊醛2-ethyl-4-methylpetanal烷醛烷醛ane-alb b-甲基戊醛甲基戊醛 或或 3-甲基戊醛甲基戊醛b b-methylpetanal23-甲基环己基甲醛甲基环己基甲醛3-methylcyclohexanecarbaldyhyde苯甲醛苯甲醛benzenecarbaldehyde benzaldehyd

2、ep-硝基苯甲醛硝基苯甲醛p-nitrobenzenecarbaldehyde3-甲基甲基-4-己烯醛己烯醛3-methyl-4-hexenal3二、酮的命名二、酮的命名Rule:选主链选主链,定母体；编号；排序定母体；编号；排序烷酮烷酮ane-anone 丙酮丙酮propanone acetone 5-甲基甲基-3-己酮己酮5-methyl-3-hexanone 4-甲基环己酮甲基环己酮4-methylcyclohexanone 1-苯基苯基-1-丙酮丙酮1-phenyl-1-propanone 2,4-己二己二酮酮2,4-hexanedione 4-己烯己烯-2-酮酮4-hexen-2-o

3、ne4化合物普通命名法IUPAC命名法熔点/沸点/溶解度g/100 g H2O甲醛HCHOformaldehydeformaldehyde-9221易溶乙醛CH3CHOacetaldehydeacetaldehyde-1212116丙醛CH3CH2CHOpropionaldehydepropanal-81497丁醛CH3(CH2)2CHOn-butyraldehydebutanal-9976微溶戊醛CH3(CH2)3CHOn-valeraldehydepentanal-92103微溶苯甲醛PhCHObenzaldehydebenzaldehyde-261780.3丙酮CH3COCH3aceto

4、nepropanone-9556丁酮CH3CH2COCH3ethyl methyl ketone2-butanone-8680262-戊酮CH3(CH2)2COCH3methyl propyl ketone2-pentanone-781026.33-戊酮C2H5COC2H5dimethyl ketone3-pentanone-401025环己酮cyclohexanonecyclohexanone-451552.4苯乙酮PhCOCH3methyl phenyl ketone1-phenyl-1-ethanone21202不溶苯丙酮PhCOCH2CH3ethyl phenyl ketone1-ph

5、enyl-1-propanone21218不溶二苯酮PhCOPhdiphenyl ketoneDiphenyl methanone48306不溶2 醛酮的物质性质醛酮的物质性质53 醛酮的化学性质醛酮的化学性质一、羰基的结构与反应特征一、羰基的结构与反应特征sp2杂杂化，平面结构化，平面结构sp3杂化，四面体杂化，四面体亲核加成反应亲核加成反应6二、羰基的亲核加成反应二、羰基的亲核加成反应1.加加HCNa a-羟基羟基酸酸a a-氨基氨基醇醇7Mechanism实验证据：加少量碱加速反应的进行实验证据：加少量碱加速反应的进行相对活性：相对活性：Problems:比较如下化合物与比较如下化合物与

6、HCN反应的活性大小反应的活性大小芳环与羰基芳环与羰基p-p p共轭，减弱羰基碳正性共轭，减弱羰基碳正性8ABED脂肪族醛酮与脂肪族醛酮与HCN反应活性，主要受空间因素影响反应活性，主要受空间因素影响(5)将如下化合物与将如下化合物与HCN反应的活性大小排序反应的活性大小排序ACB芳香族醛酮与芳香族醛酮与HCN反应活性，主要受电子效应的影响反应活性，主要受电子效应的影响9反应范围反应范围RCHO RCOCH3 8碳以下的环酮碳以下的环酮2.与与饱和饱和NaHSO3溶液反应溶液反应亲核中心为亲核中心为S，不是不是O反应范围反应范围：RCHO RCOCH3 8碳以下的环酮碳以下的环酮103.与与R

7、OH加成加成Mechanism半缩醛半缩醛酸的作用活化羰基，增大羰基的碳正性酸的作用活化羰基，增大羰基的碳正性缩醛缩醛11缩酮缩酮分水器分水器缩醛缩醛缩醛缩醛(酮酮)的分解的分解缩醛缩醛(酮酮)在碱性条件下是稳定的，但对酸敏感在碱性条件下是稳定的，但对酸敏感12保护羰基保护羰基134.与与RSH（硫醇）加成硫醇）加成硫代缩醛（酮）硫代缩醛（酮）14Problem155.与与H2O加成加成K平衡平衡的大小取决于羰基上的取代基的大小取决于羰基上的取代基166.与金属有机试剂与金属有机试剂RM加成加成RM:RMgBr,RLi,RC=CNa制备各种醇的方法制备各种醇的方法RMgBr与与RLi的区别的区

8、别177.与与氨氨的衍生物加成的衍生物加成反应通式：反应通式：1819活化羰基活化羰基NH2失活失活羰基试剂羰基试剂水解水解20三、涉及羰基三、涉及羰基a a-H的反应的反应1.a a-H的的酸性及烯醇平衡酸性及烯醇平衡烯醇平衡烯醇平衡212.a-a-卤代卤代及及卤仿卤仿反应反应A.酸酸催化下的催化下的卤代卤代反应反应动力学实验：动力学实验：反应速度与羰基化合物以及酸的浓度相关，反应速度与羰基化合物以及酸的浓度相关，但与卤素但与卤素 的浓度无关的浓度无关结论：结论：反应的决速步骤在卤素参与反应之前反应的决速步骤在卤素参与反应之前22Mechanismfastslow酸催化烯醇化酸催化烯醇化fa

9、stfast自动催化反应自动催化反应23B.碱催化下的碱催化下的卤代卤代反应反应Mechanismfastslow24卤仿卤仿碘仿反应碘仿反应黄色黄色25碘仿反应的应用碘仿反应的应用鉴别有机分子中是否具有鉴别有机分子中是否具有结构单元结构单元反应的方向反应的方向酸性条件：卤代反应发酸性条件：卤代反应发生在取代基多的生在取代基多的a a碳上碳上稳定性稳定性3o2o1oCH3氢优先迁移氢优先迁移35五、还原反应五、还原反应1.还原为醇还原为醇A.催化氢化催化氢化催化氢化活性：催化氢化活性：CHO C=C RCOR选择性差选择性差36B.化学还原化学还原LiAlH4,NaBH4选择性好选择性好LiA

10、lH4:可还原可还原COR,CO2H,CN,NO2NaBH4:一般只能还原醛酮羰基一般只能还原醛酮羰基37C.麦尔外因彭多夫还原麦尔外因彭多夫还原(Meerwein-Ponndorf)可逆可逆Mechanism负氢转移负氢转移38欧芬脑氧化欧芬脑氧化(Oppenauer)可逆可逆Mechanism醇醇交换交换39D.金属还原金属还原单分子还原：单分子还原：Na/C2H5OH;Fe/CH3CO2HMechanism负离子自由基负离子自由基40双分子还原：双分子还原：Mg,Mg-Hg齐齐/非质子性溶剂非质子性溶剂还原偶联还原偶联Mechanism412.还原为烃还原为烃A.Clemmensen还原

11、还原B.Wolff-Kischer还原还原黄鸣龙改进黄鸣龙改进42MechanismC.硫代缩酮的还原硫代缩酮的还原433.歧化反应歧化反应Cannizzaro反应反应无无a a-HMechanism负氢负氢转移转移亲核加成亲核加成44交叉歧化反应交叉歧化反应四种反应方式四种反应方式甲醛羰基活性高，优先受到甲醛羰基活性高，优先受到OH-的进攻的进攻45六、其它重要反应六、其它重要反应1.Wittig反应反应Wittig试剂磷叶立德试剂磷叶立德(Yilde)A.Wittig试剂的制备试剂的制备46B.Wittig反应的机理反应的机理47C.Wittig反应的应用反应的应用482.安息香缩合反应安

12、息香缩合反应Mechanism失去质子失去质子决速步骤决速步骤49原因：吸电子取代基减弱碳负离子的亲核性原因：吸电子取代基减弱碳负离子的亲核性 给电子取代基减弱羰基碳的碳正性给电子取代基减弱羰基碳的碳正性决速步决速步反应中提供碳负反应中提供碳负离子，亲核性大离子，亲核性大反应中提供羰基反应中提供羰基碳，其碳正性大碳，其碳正性大503.贝克曼重排贝克曼重排(Beckman)-反酮肟重排反酮肟重排Mechanism特点：分子内的反式重排特点：分子内的反式重排手性碳构型保持手性碳构型保持51七、羰基加成反应的立体化学七、羰基加成反应的立体化学产生一个新产生一个新的手性中心的手性中心R,R中不含手性碳

13、，则得到外消旋体中不含手性碳，则得到外消旋体52Cram规则规则:不对称醛酮与亲核试剂加成时，亲核试剂优先从醛酮加成不对称醛酮与亲核试剂加成时，亲核试剂优先从醛酮加成 构象中空间位阻较小的一边，既较小基团一边进攻羰基构象中空间位阻较小的一边，既较小基团一边进攻羰基优势构象优势构象：手性碳原子上最大基团与羰基处于反式共平面时，：手性碳原子上最大基团与羰基处于反式共平面时，其构象最稳定其构象最稳定5354八、八、a a,b b-不饱和醛酮的反应不饱和醛酮的反应1.亲核加成亲核加成醛羰基活性高，倾向于醛羰基活性高，倾向于1,2-加成；酮倾向于加成；酮倾向于1,4-加成加成55A.与与HCN加成加成B

14、.与与RMgX加成加成RMgX与加成与加成a a,b b-不饱和醛酮作用，不饱和醛酮作用，1,2-加成倾向大，但如羰基上有加成倾向大，但如羰基上有较大位阻取代基，则倾向于较大位阻取代基，则倾向于1,4-加成加成56C.与与RLi加成加成RLi试剂活性高，倾向于试剂活性高，倾向于1,2-加成加成D.与与R2CuLi加成加成R2CuLi倾向于倾向于1,4-加成加成572.亲电加成亲电加成与与HX加加成成，一一般为般为1,4-加成加成Br2褪色褪色584 醛酮的制备醛酮的制备一、醛的合成一、醛的合成1.1.炔水合，胞二卤代物水解炔水合，胞二卤代物水解592.2.芳烃氧化芳烃氧化3.3.伯醇氧化伯醇氧

15、化604.Reimer-Tiemer反应反应5.酰氯的部分还原酰氯的部分还原A.Rosenmund还原还原61B.化学还原化学还原LiAlH(OC(CH3)336.酯与腈的部分还原酯与腈的部分还原62二、酮的制备二、酮的制备1.甲基酮的合成甲基酮的合成RCOCH32.仲醇的氧化仲醇的氧化633.芳香酮的合成芳香酮的合成4.酰氯与有机铜化合物的反应酰氯与有机铜化合物的反应5.腈与有机镁腈与有机镁(锂锂)的反应的反应6465Key Reactions1.Reaction with Grignard Reagents2.Treatment of formaldehyde with a Grignar

16、d reagent followed by hydrolysis gives a primary alcohol.Similar treatment of any other aldehyde gives a secondary alcohol.Treatment of a ketone gives a tertiary alcohol.2.Reaction with Organolithium ReagentsReactions of aldehydes and ketones with organolithium reagents are similar to those with Gri

17、gnars reagents.3Reactions with Anions of Terminal AlkynesTreatment of an aldehyde or ketone with the alkali metal salt of a terminal alkyne followed by hydrolysis gives an a a-alkynyalchol.4.Reaction with HCN to form Cyanohydrins For aldehydes and most sterically unhindered aliphatic ketones,equilib

18、rium favors formation of the cyanohydrin.For aryl ketones,equilibrium favors starting materials,and little cyanohydrin is obtained.665.The Wittig Reaction Treatment of an aldehyde or ketone with a triphenylphosphonium ylide gives an oxaphosphetane intermediate,which fragments to give triphenylphosph

19、ine oxide and an alkene.6.HydrationThe degree of hydration is greater for aldehydes than for ketones.7.Addition of Alcohols to Form Hemiacetals Hemiacetals are only minor components of an equilibrium mixture of aldehyde or ketone and alcohol,except where the OH and the C=O are parts of the same mole

20、cule and a five-or six-membered ring can form.8.Addition of alcohols to Form Acetals Formation of acetals is catalyzed by acid.Acetals are stable to water and aqueous base but are hydrolyzed in aqueous acid.Acetals are valuable as carbonyl-protecting groups.679.Addition of Sulfur Nucleophiles:Format

21、ion of 1,3-Dithianes The most commonly used thiol for preparation of thioacetals is 1,3-propanedithiol.The product is called a 1,3-dithiane.10.Alkylation of Anions Derived from Aldehyde 1,3-Dithianes Treatment of an aldehyde 1,3-dithiane(pKa 31)with butyllithium gives an anion.This anion can enter i

22、nto substitution reactions with primary alkyl,allylic,and benzylic halides and addition reactions with the carbonyl group pf aldehydes and ketones.11.Addition of Ammonia and Its Derivatives:Formation of Imines Addition of ammonia or a primary amine to the carbonyl group of an aldehyde or ketone form

23、s a tetrahedral carbonyl addition compound.Loss of water from this intermediate gives an imine.12.Addition of Secondary Amines:Formation of Enamines Addition of Secondary amine to the carbonyl group of an aldehyde or ketone forms a tetrahedral carbonyl addition intermediate.Acid-catalyzed dehydratio

24、n of this intermediate gives an enamine.6813.Addition of Hydrazine and Its Derivatives Treatment of an aldehyde or ketone with hydrazine gives a hydrazone.Derivatives of hydrazine react similarly.14.Keto-Enol Tautomerism The keto form predominates at equilibrium,except for those aldehydes and ketone

25、s in which the enol is stabilized by resonance or hydrogen bonding.15.Deuterium Exchange at the a a-Carbon Acid-or base-catalyzed deuterium exchange at an a a-carbon involves formation of an enol or enolate anion intermediate.16.Halogenation at the a a-carbon The rate-limiting step in acid-catalyzed

26、 a-halogenation is formation of an enol.In base-promoted a a-halogenation,it is formation of an enolate anion.6917.The haloform Reaction The haloform reaction oxidizes a methyl ketone to a carboxylic acid.18.Oxidation of an Aldehyde to a Carboxylic Acid The aldehyde group is among the most easily ox

27、idized functional groups.Oxidizing agents include KMnO4,K2Cr2O7,Tollens reagent,H2O2,and O2.19.Oxidation of a Ketone to an Ester:The Baeyer-Villiger RearrangementOxidation of a ketone by a peroxyacid involves nucleaophilic addition to the carbonyl group of the ketone to form a tetrahedral carbonyl a

28、ddition intermediate followed by molecular rearrangement to give an ester.20.Catalytic Reduction Catalytic reduction of the carbonyl group of an aldehyde or ketone to an alcohol group is simple to carry out and yields of alcohol are high.A disadvantage of this method is that some other functional gr

29、oups,including carbon-carbon double and triple bonds,may also be reduced.7021.Metal Hydride Reduction Both LiAlH4 and NaBH4 are selective in that neither reduces isolated carbon-carbon double or triple bonds.22.Clemmensen Reduction of an aldehyde or ketone Reduction of the carbonyl group of an aldeh

30、yde or ketone using amalgamated zinc in the presence of concentrated hydrochloric acid gives a methylene group.23.Wolff-Kishner Reduction of an Aldehyde or Ketone Formation of a hydrazone followed by treatment with base,commonly KOH in diethylene glycol or potassium tert-butoxide in dimethyl sulfoxide,reduces the carbonyl group of an aldehyde or ketone to a methylene group.71作业：作业：P412 2 4 5 10 11 13 14 15 17 19 20 22 2372