附件2 粒大浮 教 案 2003~~2004学年第Ⅱ学期 院(系、所、部)化学与环境学院有机化学研究所 教研室有机化学 课程名称有机化学(双语教学 授课对象化学教育 授课教师杨定乔 职称职务教授 教材名称 Organic Chemistry 2004年03月01日
附件 2 教 案 2003~~ 2004 学年 第 II 学期 院（系、所、部）化学与环境学院有机化学研究所 教 研 室 有机化学 课 程 名 称 有机化学(双语教学) 授 课 对 象 化学教育 授 课 教 师 杨定乔 职 称 职 务 教授 教 材 名 称 Organic Chemistry 2004 年 03 月 01 日
有机化学(双语教学)课程教案 授课题目(教学章节或主题):第十一章.醛和酮|授课类型|理论课 Aldehydes and Ketones 第1周第55-60 授课时间 教学目标或要求:了解醛和酮的分类,命名及同分异构现象。了解醛酮亲核加成反应 历程及其制备方法。重点掌握亲核加成反应的反应历程。 教学内容(包括基本内容、重点、难点) 醛、酮 本章的重点是醛、酮的重要反应及其应用和有关反应机理。重要反应有亲核加成反应 缩合反应、α-H取代反应和氧化还原反应等。反应机理主要指亲核加成机理、羟醛缩 合机理等。难点是对结构与性质的关系、影响醛、酮亲核加成反应的因素和反应的立 体选择性的认识和理解。 aldehydes Ketones: Nomenclature Simple aldehydes and ketones are named using the standard rules of nomenclature which we have used in the past with the following specific changes 1. Aldehydes are named by replacing the term inal -e of the parent alkane with the suffix -al; the suffIx for ketone Ethanal (Acetaldehyde) 2-methylpropanal 2-propanone(Acetone) 2-methyl-2-butanone
有机化学(双语教学) 课程教案 授课题目（教学章节或主题）：第十一章．醛和酮 （Aldehydes and Ketones） 授课类型 理论课 授课时间 第 1 周第 55-60 节 教学目标或要求：了解醛和酮的分类，命名及同分异构现象。了解醛酮亲核加成反应 历程及其制备方法。重点掌握亲核加成反应的反应历程。 教学内容（包括基本内容、重点、难点）： 醛、酮 本章的重点是醛、酮的重要反应及其应用和有关反应机理。重要反应有亲核加成反应、 缩合反应、α-H 取代反应和氧化还原反应等。反应机理主要指亲核加成机理、羟醛缩 合机理等。难点是对结构与性质的关系、影响醛、酮亲核加成反应的因素和反应的立 体选择性的认识和理解。 Aldehydes & Ketones: Nomenclature Simple aldehydes and ketones are named using the standard rules of nomenclature which we have used in the past with the following specific changes: 1. Aldehydes are named by replacing the terminal -e of the parent alkane with the suffix -al; the suffix for ketones is -one
2. The parent chain selected must conta in the carbonyl gro 3. Number the carbon chain, beginning at the end nearest to the carbonyl group 4. Number the substituents and write the name, listing substituents alpha betically 3-cyclohexenone O? 3-nitrobenzaldehyde 2-hexan 4-hexen-2-one When an aldehyde is a substituent on a ring, it is referred to as a- carbaldehyde group Cyclohexanecarbaldehyde Benzenecarbaldehyde ( Benzaldehyde 6. When the-COR group becomes a substituent on another chain, it is referred to as an acyl group and the name is formed using the suffix -yl Acetyl 7. When the carbonyl group becomes a substituent on another chain, it is referred to as an oxo group 5-oxohexanal
2. The parent chain selected must contain the carbonyl group. 3. Number the carbon chain, beginning at the end nearest to the carbonyl group. 4. Number the substituents and write the name, listing substituents alphabetically. 5. When an aldehyde is a substituent on a ring, it is referred to as a -carbaldehyde group. 6. When the -COR group becomes a substituent on another chain, it is referred to as an acyl group and the name is formed using the suffix -yl. 7. When the carbonyl group becomes a substituent on another chain, it is referred to as an oxo group
Some examples 1-phenyr2-propanone czw3-methyicycloheranecar aldehyde pentanediol 3ethyl-4-pentenal Reactions of aldehydes Ketones The Grignard Reaction: The reaction of an alkyl, aryl or vinyl halide with magnesium metal in ether solvent, produces an organometallic complex of uncertain structure, but which behaves as if it has the structure r-Mg-X and is commonly referred to as a Grignard Reagent. ether R→x+Mg R-Mgx R=1°2°,or3°akyl, aryl or vinyl X=C1. Br or I R-MoX The R" group in this complex (alkyl, aryl or vinyl), acts as if it was a stabilized carbanion and Grignard reagents react with water and other compounds containing acidic hydrogens to give hydrocarbons (just as would be expected for a well-behaved, highly basic carbanion). In the absence of acidic hydrogens, the Grignard reagent can function as a powerful nucleophile, and is most often used in addition reactions involving carbony l compounds, as shown above. The product of these addition reactions is typically a secondary or tertiary alcohol (primary alcohols can be formed by reaction with formaldehyde), as shown in the examples below; in these the carbonyl and halide portions of the molecules have been colored blue and red, respectively, to assist in understanding the component parts of the final product
Some Examples: Reactions of Aldehydes & Ketones The Grignard Reaction: The reaction of an alkyl, aryl or vinyl halide with magnesium metal in ether solvent, produces an organometallic complex of uncertain structure, but which behaves as if it has the structure R-Mg-X and is commonly referred to as a Grignard Reagent. The "R" group in this complex (alkyl, aryl or vinyl), acts as if it was a stabilized carbanion and Grignard reagents react with water and other compounds containing acidic hydrogens to give hydrocarbons (just as would be expected for a well-behaved, highly basic carbanion). In the absence of acidic hydrogens, the Grignard reagent can function as a powerful nucleophile, and is most often used in addition reactions involving carbonyl compounds, as shown above. The product of these addition reactions is typically a secondary or tertiary alcohol (primary alcohols can be formed by reaction with formaldehyde), as shown in the examples below; in these the carbonyl and halide portions of the molecules have been colored blue and red, respectively, to assist in understanding the component parts of the final products
1. Melete Hgo -Br Grether 2.H3O Hydration of aldehydes Ketones The hydration of carbony l compounds is an equilibrium process and the extent of that equilibrium generally paralle ls the reactivity of the parent aldehyde or ketone towards nucleophilic substitution aldehydes are more reactive than ketones and are more highly hydrated at quilibrium. CH3 H H H2O Formation of Cyanohydrins: The reaction of carbonyl compounds with HCN is an equilibrium process and, again, the extent of that equilibrium generally parallels the reactivity of the parent aldehyde or ketone towards nucleophilic substitution
Hydration of Aldehydes & Ketones: The hydration of carbonyl compounds is an equilibrium process and the extent of that equilibrium generally parallels the reactivity of the parent aldehyde or ketone towards nucleophilic substitution; aldehydes are more reactive than ketones and are more highly hydrated at equilibrium. Formation of Cyanohydrins: The reaction of carbonyl compounds with HCN is an equilibrium process and, again, the extent of that equilibrium generally parallels the reactivity of the parent aldehyde or ketone towards nucleophilic substitution
Reaction with Amines: The reaction of carbony l compounds with amines involves the formation of an intermediate carbinolamine which undergoes dehydration to form an immonium cation which can loose a proton to form the neutral imine Hah +Ho H由H H2N Some examples of common imine-forming reactions are given be low: NHOH +H. hydroxylamine 8 micar baz加ne Hoo semicarbazide H20 2 4dimitrophenyhydrazine .. a 2 dinitrophenylhydrazone Imines formed from secondary amines can loose a proton from the a-carbon to form an enamine. Because of resonance, enamines maintain a partial carbanion character on the a-carbon and can be utilized as nucleophiles, as will be
Reaction with Amines: The reaction of carbonyl compounds with amines involves the formation of an intermediate carbinolamine which undergoes dehydration to form an immonium cation which can loose a proton to form the neutral imine. Some examples of common imine-forming reactions are given below: Imines formed from secondary amines can loose a proton from the −carbon to form an enamine. Because of resonance, enamines maintain a partial carbanion character on the −carbon and can be utilized as nucleophiles, as will be
discussed in the section on alpha alkylations CHCH CH3 CH2- CH2CH3 3c H3c t 3C an enamine CH3cH2~伊CH2H Ketal and Acetal Formation: Ketones and aldehydes react with excess alcohol in the presence of acid to give ketals and acetals, respectively. The mechanism of acetal formation involves equilibrium protonation, attack by alcohol, and then loss of a proton to give the neutral hemiacetal (or hemiketal).The hemiacetal undergoes protonation and loss of water to give an oxocarbonium ic which undergoes attack by another mole of alcohol and loss of a proton to give the final product; note that acetal (or ketal) formation is an equilibrium process H R-OH FmalProdnct the acetalor ketal R-OH H Some examples of acetal and ketal formation are given bele
discussed in the section on "alpha alkylations". Ketal and Acetal Formation: Ketones and aldehydes react with excess alcohol in the presence of acid to give ketals and acetals, respectively. The mechanism of acetal formation involves equilibrium protonation, attack by alcohol, and then loss of a proton to give the neutral hemiacetal (or hemiketal). The hemiacetal undergoes protonation and loss of water to give an oxocarbonium ion, which undergoes attack by another mole of alcohol and loss of a proton to give the final product; note that acetal (or ketal) formation is an equilibrium process. Some examples of acetal and ketal formation are given below:
CH3OHPH DHH LoH HaC The Wittig Reaction: Ketones and aldehydes react with phosphorus ylides to form alkenes. Phosphorus ylides are prepared by an S,2 reaction between an alkyl halide and tripheny phosphine, followed by deprotonation by a strong base such as n-butyllithium. The mechanism of the Wittig reaction involves nucleophilic addition to give an intermediate betaine, which decomposes to give the alkene and tripheny phosphine oxide. The Wittig reaction works well to prepare mono di- and tri-substituted alkenes; tetra-substituted alkenes cannot be prepared by this method R=alkyl or h a phosphorus yhe R2C-P(ChS)3 betaine e6P’cHls 9(6H R2C-P(C6Hslo Oxidation Reduction of aldehydes and Ketones Preparation of Alcohols by Reduction of Aldehydes and Ketones: Reduction of simple aldehydes and
The Wittig Reaction: Ketones and aldehydes react with phosphorus ylides to form alkenes. Phosphorus ylides are prepared by an SN2 reaction between an alkyl halide and triphenylphosphine, followed by deprotonation by a strong base such as n-butyllithium. The mechanism of the Wittig reaction involves nucleophilic addition to give an intermediate betaine, which decomposes to give the alkene and triphenylphosphine oxide. The Wittig reaction works well to prepare monodi- and tri-substituted alkenes; tetra-substituted alkenes cannot be prepared by this method. Oxidation & Reduction of Aldehydes and Ketones Preparation of Alcohols by Reduction of Aldehydes and Ketones: Reduction of simple aldehydes and
ketones with BH4 yields the corresponding alcohol directly. The reaction works well for simpl compounds, but reaction of BH4 with a-B-unsaturated aldehydes and ketones can result in significant reduction of the double bond HBC-C-OH aldehydes 2.H3O CH3-C--CH3 1.BH4 2.H3O A much more powerful reductant is LiAlH, which will reduce al dehyde, ketones esters, carboxylic acids and nitriles. Some sample reactions are shown below ether 1. LiAlH. ether 2. H3O oH 1. LiAlH,. ether 2. H3O As seen in the first example, the reduction of carboxylate esters results in the addition of two moles of hydride to the carbony l carbon, with loss of the alcohol portion of the ester, forming the corresponding primary alcohol H-HBLiAl H Although the reduction of esters with lialH4 proceeds to produce the alcohol, reduction of carboxylate esters by diisobutylaluminum hydride(DIBAH)stops at the aldehyde
ketones with BH4 - yields the corresponding alcohol directly. The reaction works well for simple compounds, but reaction of BH4 - with −−unsaturated aldehydes and ketones can result in significant reduction of the double bond. A much more powerful reductant is LiAlH4, which will reduce aldehydes, ketones, esters, carboxylic acids and nitriles. Some sample reactions are shown below: As seen in the first example, the reduction of carboxylate esters results in the addition of two moles of hydride to the carbonyl carbon, with loss of the alcohol portion of the ester, forming the corresponding primary alcohol. Although the reduction of esters with LiAlH4 proceeds to produce the alcohol, reduction of carboxylate esters by diisobutylaluminum hydride (DIBAH) stops at the aldehyde
-= HS- diisobutylaluminium hydro (DIBAH) Wolff-Kishner Reduction: The imine formed from an aldehyde or ketone on reaction with hydrazine(NH,NH, )is unstable in base, and undergoes loss of N to give the corresponding hydrocarbon. H2N-NH2 H unstable alkyl car banion Clemmensen Reduction: Carbony l compounds can also be reduced by the Clemmensen reduction using zinc-mercury amalgam in the presence of acid; the mechanism most likely involves free radicals Zn(Hg) Zn(Hg) The Formation of Thioketal and Thioacetals: Ketones and aldehydes react with excess thiol in the presence of acid to give thioketals and thioacetals respectively. These compounds are smoothly reduced by Raney-Nickel to give the corresponding hydrocar
Wolff-Kishner Reduction: The imine formed from an aldehyde or ketone on reaction with hydrazine (NH2NH2) is unstable in base, and undergoes loss of N2 to give the corresponding hydrocarbon. Clemmensen Reduction: Carbonyl compounds can also be reduced by the Clemmensen reduction using zinc-mercury amalgam in the presence of acid; the mechanism most likely involves free radicals. The Formation of Thioketal and Thioacetals: Ketones and aldehydes react with excess thiol in the presence of acid to give thioketals and thioacetals, respectively. These compounds are smoothly reduced by Raney-Nickel to give the corresponding hydrocarbons
