西北农林科技大学：《有机化学 Organic chemistry》课程PPT教学课件（2014）Chapter 23 Condensation and Alpha Substitution of Carbonyl Compounds

有机化学ORGANIC CHEMISTRY 主讲：主依儒87092829(0) 理学院应化系理科接2层C206 Organic Chemistry,6th Edition L.G.Wade,Jr. Chapter 23 Condensation and Alpha Substitution of Carbonyl Compounds Key Notes Enol-keto tautomerism,Todoform Reaction,Aldol Condensation,Claisen Condensation,Acetoacetic Ester Synthesis; The Michael Reactionj Homework:P806:23-28,23-30(a,b,c,d)

Chapter 23 Condensation and Alpha Substitution of Carbonyl Compounds Organic Chemistry, 6th Edition L. G. Wade, Jr. Key Notes Enol–keto tautomerism,Iodoform Reaction,Aldol Condensation,Claisen Condensation,Acetoacetic Ester Synthesis； The Michael Reaction; 有机化学ORGANIC CHEMISTRY 主讲：王俊儒 87092829(O) 理学院应化系理科楼2层C206 Homework: P806: 23-28; 23-30(a,b,c,d)

自秋标 CONTENTS 1.REVIEW: Enol -keto tautomerism 2.Iodoform and Haloform Reaction(碘仿反应) 3.Aldol Condensation（羟醛缩合) 4.Claisen Condensation(酯缩合) 5.Acetoacetic Ester Synthesis;Malonic Ester Synthesis(三乙合成；丙二酸酯合成路线) 6.Conjugate Additions: The Michael Reaction(迈克尔加成)

CONTENTS 1. REVIEW： Enol – keto tautomerism 2. Iodoform and Haloform Reaction（碘仿反应） 3. Aldol Condensation（羟醛缩合） 4. Claisen Condensation （酯缩合） 5. Acetoacetic Ester Synthesis；Malonic Ester Synthesis（三乙合成；丙二酸酯合成路线） 6. Conjugate Additions: The Michael Reaction（迈克尔加成）

1.REVIEW: Enol keto tautomerism OH R Keto tautomer Enol tautomer The tautomerism proceeds by either acid or base catalysis. Step 1 Step 2 H

1.REVIEW： Enol – keto tautomerism The tautomerism proceeds by either acid or base catalysis

:OH H Deprotonation of a Carbonyl Compound at the a-Carbon a-Carbon 0: BH Enolate ion pk≈l6-l8(aldehydes) 19-21(ketones)

酸性；烯醇式；取代 氢化；亲核加成： 碱性及质子化： ● 6 :氧化 O-K+ 0 CH,CH-CH2 Deprotonation H 10%KOH.CHCH-OH CHCH=CH2 H Reprotonation CH,CH-CH CH. CH H H >95% HsC6 CH3CH2O-. HsC6 CH3CH2O-. HsC6 -CCH: CH3CH2OH CH3CH2OH CCH H.C* HC H.C CH3 H (S)-3-Phenyl- Enolate ion (R)-3-Phenyl- 2-butanone (Achiral) 2-butanone

C O C C δ - δ + H δ + C O H C δ - δ + H δ + 酸性；烯醇式; 取代 氢化；亲核加成 碱性及 质子化 氧化 δ +

脱羧和还原 R CH H 酸性 H --Y 衍生物 a-H的取代 被取代

酸性 被取代 脱羧和还原 -H的取代 R CH C O H H O ---Y 衍生物

Alpha Substitution Replacement of a hydrogen on the carbon adjacent to the carbonyl,C=O. Step 1:Deprotonation Step 2:Attack on electrophile E base: enolate ion Copyright 2005 Pearson Prentice Hall,Inc

Alpha Substitution Replacement of a hydrogen on the carbon adjacent to the carbonyl, C=O

2.a Halogenation Iodoform Reaction (碘仿反应) 卤代反应：+X2 RCH2-C-H(R)_ r2 RCHBrC-H(R) H+ 0 Br-BrCHCO2H) H0,70°C H-CH2CCH3 BrCH2CCH3 HBr 44% Bromoacetone

2.  Halogenation & Iodoform Reaction （碘仿反应） 卤代反应：+X2 O RCHBrC H(R') Br 2 RCH2 C H(R') O H+

Multiple Halogenations The a-halo ketone produced is more reactive than ketone. Enolate ion stabilized by e-withdrawing halogen. OH R-CH-CH3 I2 R-C-CH 2HI excess 12 OH 0H,H20 Copyright 2005 Pearson Prentice Hall,Inc

Multiple Halogenations ◼The -halo ketone produced is more reactive than ketone. ◼Enolate ion stabilized by e--withdrawing halogen. O H Cl Cl 2 OH , H2O _ O Cl Cl O Cl C Cl l O Cl C Cl l Cl

卤仿（碘仿）反应 CH3 I2/0H- cr t-nay OH 黄↓ 或N0 CH+R')HC-O CH2CHO OHA ICH,CHO OH-/I2 I.CHCHO OH/2 I3CCHO OH-/I2 CHI3+HCOOH 规律：乙醛，甲基酮，乙醇，异丙醇均可 CH3COR(H);CH3COHR(H); ?CH3COOH

卤仿(碘仿)反应 CH3CHO ICH2CHO I2CHCHO I3CCHO CHI3+ HCOOH OH-/I2 OH-/I2 OH-/I2 OH-/I2 规律: 乙醛,甲基酮,乙醇,异丙醇均可 CH3COR(H); CH3COHR(H); ?CH3COOH C H 3 C H (R ') O I 2 /O H - 或 N aIO 黄↓ CI3 C H(R') O OH￾CHI3 + (R')HC O￾O