12.6 Aldol Reaction and Aldol Condensation

Slides:

Advertisements

Similar presentations

Aldehid dan Keton.

Advertisements

Chapter Two Polar Reaction Under Basic Conditions

Chemistry of Carbonyl Compounds (McM 19-12) Nucleophilic addition / substitution May also be acid cat.

© 2011 Pearson Education, Inc. 1 Organic Chemistry 6 th Edition Paula Yurkanis Bruice Chapter 19 Carbonyl Compounds III Reactions at the  -Carbon.

Organic Chemistry, 6th Edition L. G. Wade, Jr.

Aldehydes and ketones that have a C=O bond , but no O-H bond, cannot form hydrogen bonds with one another, as alcohols. Aldehyde and ketones therefore.

1 Nucleophilic reactions involving enolate anions Aldehydes, Ketons and other carbonyl compounds having H on α-C -> in equilibrium (in solution) -> Keto-Enol.

Copyright © 2000 by John Wiley & Sons, Inc. All rights reserved. Introduction to Organic Chemistry 2 ed William H. Brown.

Chapter 13 Substitution Alpha to Carbonyl Groups Formation and Reactions of Enolate Anions and Enols Alkylation of Ketones and Esters: S N 2 Reaction with.

REACTIONS OF  -HYDROGENS : REACTIONS OF  -HYDROGENS : ALDOL AND CLAISEN ALDOL AND CLAISEN CONDENSATION REACTIONS CONDENSATION REACTIONS.

Chapter 23. Carbonyl Condensation Reactions

191 Chapter 21: Ester Enolates 21.1: Ester  Hydrogens and Their pK a ’s. The  -protons of esters are less acidic that ketones and aldehydes. Typical.

ALDEHYDES AND KETONES BY: SALEHA SHAMSUDIN.

Condensation and Conjugate Addition Reactions of Carbonyl Compounds

Condensation and Conjugate Addition Reactions of Carbonyl Compounds

1 Nucleophilic reactions involving enolate anions (2) Aldehydes, Ketons and other carbonyl compounds having H on α-C -> in equilibrium (in solution) ->

Keto-enol tautomerization enolization “normal” aldehydes and ketones K eq = ~

Carbonyl Compounds III

14.3 Aldol Reaction and Claisen Condensation in Biology

Alkylation of Aldehydes and Ketones 18-4 Alkylation of enolates can be difficult to control. The alkylation of an aldehyde or ketone enolate is an example.

OrgChem- Chap20 1 Chapter 20 Enolates / Other Carbon Nucleophiles C-C bond formation is very important  larger, more complex organic molecule can be made.

CARBONYL CONDENSATION REACTIONS

The Haloform Reaction Under basic conditions, halogenation of a methyl ketone often leads to carbon-carbon bond cleavage. Such cleavage is called the haloform.

Chapter 23. Carbonyl Condensation Reactions

Chapter 23. Carbonyl Condensation Reactions

Ch. 18 Lect. 2 Complex Carbonyl Reactions I.Aldol Condensation A.Two aldehyde molecules can react to form an  -unsaturated aldehyde product 1)This reaction.

John E. McMurry Paul D. Adams University of Arkansas Chapter 23 Carbonyl Condensation Reactions.

CH 23: Carbonyl Condensation Reactions

17.4 How Aldehydes and Ketones React (Part III)

1 Carbonyl Condensation Reactions. 2 Very General Reaction. What is needed? –A Ketone or aldehyde – ONE reactant must have  -Hydrogens –Base (NaOH)

Aldehydes and Ketones II Aldol Reactions

Chapter 24 Carbonyl Condensation Reactions The Aldol Reaction In the aldol reaction, two molecules of an aldehyde or ketone react with each other.

Chapter 24 Carbonyl Condensations

Chapter 23. Carbonyl Condensation Reactions

Chapter 18: Enols and Enolates Overview Enols : Enolates :

Dr. Hayder kh. Q. Ali School of Bioprocess Engineer UniMAP.

23.7 The Claisen Condensation Reaction

Carbonyl Condensation Reactions

1 Carbonyl Condensation Reactions Carbonyl compounds are both the electrophile and nucleophile in carbonyl condensation reactions.

Properties of ,  -Unsaturated Aldehydes and Ketones 18-8 Conjugated unsaturated aldehydes and ketones are more stable than their unconjugated isomers.

Enols and Enolates  Substitutions and Condensations of Ketones and Aldehydes.

WWU -- Chemistry The Claisen Ester Condensation Taken from: 1c.ppt 1c.ppt.

126 Chapter 18: Enols and Enolates 18.1: The  -Carbon Atom and its pK a.

Clickers: Which one of the following reactions would actually work as written?

18.11 Effects of Conjugation in  -Unsaturated Aldehydes and Ketones.

Chapter 17 Aldehydes and Ketones II. Aldol Reactions

Please don’t do problem 31a, but please do problem 32c.

Examples: Aldehydes and ketones

1 The Michael Reaction The ,  -unsaturated carbonyl component is often called a Michael acceptor. Carbonyl Condensation Reactions.

Carbanions | — C: – The conjugate bases of weak acids,

Addition and Condensation reactions of

Objectives for Chapter 23

Chapter 23 Carbonyl Condensation Reactions

Chapter 20 Enolates / other Carbanions

Stabilized Carbanions with One -M (I)

Chapter 18 Enols and Enolates

CARBONYL CONDENSATION REACTION DEPARTMENT OF CHEMISTRY

Chapter 23. Carbonyl Condensation Reactions

Chapter 14 Aldehydes, Ketones, and Chiral Molecules

Another Equilibrium: Reaction At The a-Position

CARBONYL COMPOUNDS ALDOL CONDENSATION

Extent of Enolization.

Dr. Pandit Khakre Asst. Prof Mrs. K.S.K. College, Beed.

Reaction pathways of methylglyoxal oligomerization

CARBONYL CONDENSATION REACTION DEPARTMENT OF CHEMISTRY

Chapter 23 Carbonyl Condensation Reactions

Alpha Substitution Alpha substitution is the substitution of one of the hydrogens attached to the a carbon for an electrophile. The reaction occurs through.

Aldol reactions.

Qualitative Iodoform Test

Presentation transcript:

12.6 Aldol Reaction and Aldol Condensation Main Menu 12.6 Aldol Reaction and Aldol Condensation General reaction: b-hydroxycarbonyl 2 3 1 Aldol reaction 2 Aldol condensation a,b-unsaturateed carbonyl

Mechanism of Aldol Reaction E-enolate Z-enolate Aldol reaction can be reversible (retro-Aldol reaction).

Examples of Aldol Reaction/Condensation -H2O

Potential Problem of Aldol Reaction Mixed aldol reaction: Desired product To avoid the formation of by-products: Add slowly

Use Selected Aldehydes for Aldol Reaction Aldehydes that have no a-hydrogens: furfural formaldehyde benzaldehyde pivaldehyde, trimethylacetaldehyde 2,2-dimethylpropanal

Intramolecular Aldol Reaction Formation of 5- or 6-membered rings. a-H 6-membered 8-membered Not formed

Intramolecular Aldol Reaction Formation of 5- or 6-membered rings. a-H 5-membered 7-membered Not formed

Intramolecular Aldol Reaction Formation of 5- or 6-membered rings. a-H 5-membered 5-membered 7-membered Not formed

Robinson Annulation: Michael Addition Followed by Aldol Condensation H+, heat Michael addition Aldol reaction

Learning Check 1. What could be the product for the following reaction?

Learning Check 2. What could be the product for the following reaction? 3. What could be the product for the following reaction?

Learning Check Main Menu 4. What could be the product for the following reaction? 2 2