Chapter 16 Aldehydes and Ketones I. Nucleophilic additions to the carbonyl group 16.1 Introduction Except for formaldehyde, the simplest aldehyde, all aldehydes have a carbonyl group, C=0 bonded on one side to a carbon and on the other side to a hydrogen. In ketones, the carbonyl group is situated between two carbon atoms. (Ar) A H—c—H R c R c R Formaldehyde Aldehydes tones 甲醛 醛
Chapter 16 Aldehydes and Ketones I. Nucleophilic additions to the carbonyl group 16.1 Introduction Except for formaldehyde, the simplest aldehyde, all aldehydes have a carbonyl group, C=O, bonded on one side to a carbon, and on the other side to a hydrogen. In ketones, the carbonyl group is situated between two carbon atoms. H C O H R C O H R C O R' (Ar) (Ar) (Ar) Formaldehyde Aldehydes Ketones 甲 醛 醛 酮
16.2 Nomenclature of aldehydes and ketones In the IUPaC system aliphatic aldehydes are named substitutively by replacing the final e of the name of the corresponding alkane with al For example H—c——HH3c—c—HCH3CH2 CHO CH3CH2CH2CHO IUPAC: Methanal Ethanal Propanal Butanal (Formaldehyde)(acetaldehyde)(propionaldehyde) 甲醛 乙醛 丙醛 丁醛
16.2 Nomenclature of aldehydes and ketones In the IUPAC system aliphatic aldehydes are named substitutively by replacing the final e of the name of the corresponding alkane with al For example H C O H H3C C O H (Formaldehyde) 甲 醛 乙 醛 Methanal Ethanal (acetaldehyde) CH3CH2CHO Propanal (propionaldehyde) CH3CH2CH2CHO Butanal 丙 醛 丁醛 IUPAC;
Aldehydes in which the-CHO group is attached to a ring system are named substitutively by adding the suffix carbaldehyde. CHO c-H C-H IUPAC; Benzenecarbaldehyde Cyclohexanecarbaldehyde 2-Naphthalenecarbaldehyde (Benzaldehyde) 苯甲醛 环己基甲醛 2-萘甲醛
Aldehydes in which the –CHO group is attached to a ring system are named substitutively by adding the suffix carbaldehyde. C O H C O H (Benzaldehyde) 苯 甲 醛 环 己 基 甲 醛 Benzenecarbaldehyde Cyclohexanecarbaldehyde 2-Naphthalenecarbaldehyde 2-萘 甲 醛 IUPAC; CHO
Aliphatic ketones are named substitutively by replacing the final e of the name of the corresponding alkane with one 12345 CH3CHE-C--CH3 CH3COCH2 CH2CH3 CH3,CH=CH2 IUPAC: 2-Butanone 2-Pentanone 4-Penten-2-one (ethyl methyl ketone)(ethyl propyl ketone) 2-丁酮 2-戊酮 4-戊烯-2-酮
Aliphatic ketones are named substitutively by replacing the final e of the name of the corresponding alkane with one C O CH3 (ethyl methyl ketone) 2-丁 酮 2-Butanone 4-Penten-2-one 4-戊 烯 -2-酮 IUPAC; CH3 CH2 CH3 COCH2 CH2 CH3 2-Pentanone (ethyl propyl ketone) CH3 COCH2 CH=CH2 1 2 3 4 5 2-戊 酮
H3—c——cH3 CH3 cotone Acetophenone Benzophenone (dimethyl ketone) (methyl phenyl ketone) (diphenyl ketone) 丙酮 苯乙酮 二苯甲酮 CHO OH H3c SO 2-Methanoylbenzoic acid 4-Ethanoylbenzenesulfonic acid (o-formylbenzoic acid (p-acetylbenzenesulfonic acid) 2-醛基苯甲酸 p-乙酰基苯磺酸
C O CH3 丙 酮 Acetone Benzophenone 二 苯 甲 酮 CH3 Acetophenone 苯 乙 酮 O CH3 O (methyl phenyl ketone) (diphenyl ketone) (dimethyl ketone) 4-Ethanoylbenzenesulfonic acid p-乙 酰 基 苯 磺 酸 2-Methanoylbenzoic acid 2-醛 基 苯 甲 酸 O OH H3 C O (p-acetylbenzenesulfonic acid) (o-formylbenzoic acid) CHO SO3 H
Some aromatic aldehydes obtained from natural sources have very pleasant fragrances. CHO CHO CHO OH OCH3 OH Benzaldehyde苯甲醛 anillin香草醛 Salicylaldehyde水杨醛 (from bitter almonds (from vanilla beans (from meadowsweet 苦杏仁 香草豆 〈植〉绣线菊
Some aromatic aldehydes obtained from natural sources have very pleasant fragrances. CHO OH CHO OH OCH3 CHO Benzaldehyde (from bitter almonds) Vanillin (from vanilla beans) Salicylaldehyde (from meadowsweet) 香草醛 〈植〉绣线菊 水 杨 醛 苦杏仁 苯 甲 醛 香草豆
CHO CHECHCHO O 肉桂醛(3-苯基丙烯醛) Piperonal胡椒醛 Cinnamaldehyde made from safrole; from cinnamon odor of heliotrope) 「植物肉桂,桂皮, 由黄樟油精制备,植向日葵气味
CHO CH=CHCHO Cinnamaldehyde (from cinnamon) Piperonal (made from safrole; odor of heliotrope) 胡 椒 醛 [植物]肉桂, 桂皮, 由 黄樟油精制 备 , [植] 向日葵气 味 , 肉桂醛 (3-苯 基 丙 烯 醛 ） O O
16.4 Synthesis of aldehydes 1. Oxidation NHCL= PCC O O R—CH3OH一 R——CHO CH2Cl Aldehyde PCC CH3(CH2)5CH2OH一 CH3(CH2) cHO CHoCI Heptane (93
16.4 Synthesis of aldehydes 1. Oxidation R CH3 OH N Cr O O O HCl PCC CH2 Cl 2 R CHO Aldehyde CH3 (CH2 ) 5 CH2 OH CH2 Cl 2 PCC CH3(CH2) 5 CHO Heptanal (93%)
2 Reduction Reduction reagens; CH OC(CH3)2 CHCH2CH3 Li|H-A|—-oc(cH3)3 H—A—cHcH2CH3 OC(CH3))3 CH3 Lithium tri-tert-butoxy aluminum hydride Isobutyl aluminum hydride DIBAL-H) 三叔-丁氧基氩化铝锂 二异丁基氬化铝 Aldehydes from Acyl chlorides; RCoCI H RCHO Aldehydes from esters; RCOCI 江RCHO Aldehydes from nitriles H,O RC=N RCHO
2 Reduction H Al OC(CH3)3 OC(CH3)2 Li OC(CH3)3 + _ Lithium tri-tert-butoxy aluminum hydride 三 叔 -丁 氧 基 氢 化 铝 锂 Reduction reagens; H Al CHCH2CH3 CHCH2CH3 CH3 Diisobutyl aluminum hydride 二 异 丁 基 氢 化 铝 (DIBAL-H) CH3 Aldehydes from Acyl chlorides; Aldehydes from esters; Aldehydes from nitriles; RCOCl RCHO RCOCl RCHO RC N RCHO [H - ] [H - ] [H - ] H2O H2O H2O
HAI(CH(CH3)CH,CH3)h2 H,O R -78°C HAI(CH(CH3)CH,CH3) H,O R COR R H 78°C HAI(CH(CH3)CH, CH3)2 H, R—cN 78°C Reduction of Esters to aldehydes OAl(i-Bu)2 HAI(CH(CH3CH2CH3)2 R OR R OR 780C H +O—A(i-Bu)2 (-OR) HO R R H
-78 oC R O Cl R O COR' R C N HAl(CH(CH3 )CH2CH3 ) 2 H2O -78 oC HAl(CH(CH3 )CH2CH3 ) 2 H2O -78 oC HAl(CH(CH3 )CH2CH3 ) 2 H2O R O H -78 o C R O OR HAl(CH(CH3 )CH2CH3 ) 2 H - R OAl(i-Bu) 2 OR H (-OR) R O H + Al(i-Bu) 2 H2O R O H - + Reduction of Esters to aldehydes