Chemistry
Reactions of Aldehydes and Ketones
The reactions of aldehydes and ketones involve a variety of chemical transformations, including nucleophilic addition, oxidation, reduction, and condensation reactions. These reactions are important in organic synthesis and are used to create a wide range of compounds with diverse functional groups and properties. Aldehydes and ketones can undergo these reactions due to the presence of the carbonyl group, which is highly reactive.
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10 Key excerpts on "Reactions of Aldehydes and Ketones"
eBook - PDF- David R. Klein(Author)
- 2016(Publication Date)
- Wiley(Publisher)
19.1 Introduction to Aldehydes and Ketones 19.2 Nomenclature 19.3 Preparing Aldehydes and Ketones: A Review 19.4 Introduction to Nucleophilic Addition Reactions 19.5 Oxygen Nucleophiles 19.6 Nitrogen Nucleophiles 19.7 Hydrolysis of Acetals, Imines, and Enamines 19.8 Sulfur Nucleophiles 19.9 Hydrogen Nucleophiles 19.10 Carbon Nucleophiles 19.11 Baeyer–Villiger Oxidation of Aldehydes and Ketones 19.12 Synthesis Strategies 19.13 Spectroscopic Analysis of Aldehydes and Ketones 19 Aldehydes and Ketones DID YOU EVER WONDER . . . why beta-carotene, which makes carrots orange, is reportedly good for your eyes? T his chapter will explore the reactivity of aldehydes and ketones. Specifically, we will see that a wide variety of nucleophiles will react with aldehydes and ketones. Many of these reactions are common in biological pathways, including the role that beta-carotene plays in promoting healthy vision. As we will see several times in this chapter, the Reactions of Aldehydes and Ketones are also cleverly exploited in the design of drugs. The reactions and principles outlined in this chapter are central to the study of organic chemistry and will be used as guid- ing principles throughout the remaining chapters of this textbook. 19.1 Introduction to Aldehydes and Ketones 845 19.1 Introduction to Aldehydes and Ketones Aldehydes (RCHO) and ketones (R 2 CO) are similar in structure in that both classes of compounds possess a C = O bond, called a carbonyl group: O Carbonyl group O R H An aldehyde R R A ketone The carbonyl group of an aldehyde is flanked by a hydrogen atom, while the carbonyl group of a ketone is flanked by two carbon atoms.
eBook - PDF- David R. Klein(Author)
- 2020(Publication Date)
- Wiley(Publisher)
20.1 Introduction to Aldehydes and Ketones 20.2 Nomenclature 20.3 Preparing Aldehydes and Ketones: A Review 20.4 Introduction to Nucleophilic Addition Reactions 20.5 Oxygen Nucleophiles 20.6 Nitrogen Nucleophiles 20.7 Hydrolysis of Acetals, Imines, and Enamines 20.8 Sulfur Nucleophiles 20.9 Hydrogen Nucleophiles 20.10 Carbon Nucleophiles 20.11 Baeyer–Villiger Oxidation of Aldehydes and Ketones 20.12 Synthesis Strategies 20.13 Spectroscopic Analysis of Aldehydes and Ketones 20 Aldehydes and Ketones DID YOU EVER WONDER . . . why beta-carotene, which makes carrots orange, is reportedly good for your eyes? T his chapter will explore the reactivity of aldehydes and ketones. Specifically, we will see that a wide variety of nucleophiles will react with aldehydes and ketones. Many of these reactions are common in biological pathways, including the role that beta-carotene plays in promoting healthy vision. As we will see several times in this chapter, the reac- tions of aldehydes and ketones are also cleverly exploited in the design of drugs. The reactions and principles outlined in this chapter are central to the study of organic chemis- try and will be used as guiding principles throughout the remaining chapters of this textbook. 20.1 Introduction to Aldehydes and Ketones 889 20.1 INTRODUCTION TO ALDEHYDES AND KETONES Aldehydes (RCHO) and ketones (R 2 CO) are similar in structure in that both classes of compounds possess a C O bond, called a carbonyl group: O Carbonyl group O R H An aldehyde R R A ketone The carbonyl group of an aldehyde is flanked by a hydrogen atom, while the carbonyl group of a ketone is flanked by two carbon atoms.
eBook - PDF- Ramesh Chandra, Snigdha Singh, Aarushi Singh(Authors)
- 2019(Publication Date)
- Arcler Press(Publisher)
Briefly, ketones and aldehydes are significant intermediates for the synthesis or assembly of complex organic molecules. Organic Reactions and their nomenclature 256 Figure 8.5: Reactions involved in the synthetic form of aldehydes and ketones. [Source: https://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/aldket1. htm] 8.4. PROPERTIES OF ALDEHYDES AND KETONES An assessment of the reactivity and characteristics of ketones and aldehydes with those of the alkenes is necessary because both have a dual bond functional group. The carbonyl group is polar, because of the superior electronegativity of oxygen, and ketones and aldehydes have greater Carbonyl Group Reactions 257 molecular dipole moments (D) than do alkenes. This polarity is illustrated by the resonance structures on the right, and the relative dipole moments of formaldehyde, other ketones and aldehydes approve the stabilizing effect that alkyl substituents have on carbocations. Therefore, we suppose, that ketones and aldehydes will have greater boiling points than alike sized alkenes. Figure 8.6: Dipole moments of different carbonyl compounds. [Source: https://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/aldket1. htm] Moreover, ketones and aldehydes are made hydrogen-bond acceptors because of the existence of oxygen with its non-bonding electron pairs and should raise their solubility of water relative to hydrocarbons. Particular instances of these associations are given in the subsequent table. Equated with the non-polar double bonds of alkenes, the polarity of the carbonyl group also has a deep impact on its chemical reactivity. Therefore, reversible addition of water to the carbonyl function is fast, whereas water addition to alkenes is infinitely slow in the nonappearance of a strong acid catalyst. Inquisitively, relative bond energies affect the thermodynamics of such addition reactions in a conflicting manner. Figure 8.7: Physical characteristics of different carbonyl compounds.
eBook - PDF- David R. Klein(Author)
- 2021(Publication Date)
- Wiley(Publisher)
19.1 Introduction to Aldehydes and Ketones 19.2 Nomenclature 19.3 Preparing Aldehydes and Ketones: A Review 19.4 Introduction to Nucleophilic Addition Reactions 19.5 Oxygen Nucleophiles 19.6 Nitrogen Nucleophiles 19.7 Hydrolysis of Acetals, Imines, and Enamines 19.8 Sulfur Nucleophiles 19.9 Hydrogen Nucleophiles 19.10 Carbon Nucleophiles 19.11 Baeyer–Villiger Oxidation of Aldehydes and Ketones 19.12 Synthesis Strategies 19.13 Spectroscopic Analysis of Aldehydes and Ketones Top (Carrot) Ints Vikmanis/Shutterstock; Bottom (Caring for eye sight by healthy eating) JerryB7/Getty Images 19 Aldehydes and Ketones DID YOU EVER WONDER . . . why beta-carotene, which makes carrots orange, is reportedly good for your eyes? T his chapter will explore the reactivity of aldehydes and ketones. Specifically, we will see that a wide variety of nucleophiles will react with aldehydes and ketones. Many of these reactions are common in biological pathways, including the role that beta-carotene plays in promoting healthy vision. As we will see several times in this chapter, the Reactions of Aldehydes and Ketones are also cleverly exploited in the design of drugs. The reactions and principles outlined in this chapter are central to the study of organic chemistry and will be used as guid- ing principles throughout the remaining chapters of this textbook. 19.1 Introduction to Aldehydes and Ketones 885 DO YOU REMEMBER? Before you go on, be sure you understand the following topics. If necessary, review the suggested sections to prepare for this chapter. • Retrosynthetic Analysis (Section 11.5) • Grignard Reagents (Section 12.6) • Oxidation of Alcohols (Section 12.10) Take the DO YOU REMEMBER? QUIZ in the online course to check your understanding.
eBook - PDF- Mark G. Moloney(Author)
- 2023(Publication Date)
- Wiley(Publisher)
1 1 Reactions of Aldehydes and Ketones and Their Derivatives B. A. Murray School of Chemical and BioPharmaceutical Sciences, Technological University of Dublin (TU Dublin), Dublin, Ireland CHAPTER MENU Formation and Reactions of Acetals and Related Species, 2 Reactions of Glucosides, 2 Reactions of Ketenes and Related Cumulenes, 4 Formation and Reactions of Nitrogen Derivatives, 5 Imines: Synthesis, and General and Iminium Chemistry, 5 Mannich and Mannich-type Reactions, 6 Stereoselective Hydrogenation of Imines, and Other Reductive Processes, 7 Cyclizations of Imines, 8 Other Reactions of Imines, 9 Oximes, Oxime Ethers, and Oxime Esters, 12 Hydrazones and Related Species, 16 C—C Bond Formation and Fission: Aldol and Related Reactions, 17 Reviews of Aldols, and General Reviews of Asymmetric Catalysis, 17 The Asymmetric Aldol, 18 The Morita–Baylis–Hillman Reaction, 18 Other Aldol and Aldol-Type Reactions, 18 Allylation and Alkynylation Reactions, 20 The Michael Addition, 20 Other Addition and Related Reactions, 21 Arylations, 21 The Wittig and Other Olefinations, 21 Hydroboration and Hydroacylation, 22 −Aminations and Related Reactions, 23 Miscellaneous Additions, 23 Reactions of Enols, Enolates, and Related Reactions, 23 Tautomerism, 23 Enol Ethers, Enol Esters, and Enolates, 24 −Halogenation, −Alkylation, and Other −Substitutions, 25 Oxidation of Carbonyl Compounds, 25 Oxidation of Aldehydes to Acids, 25 Cross-dehydrogenative and Related C–C Coupling Processes, and C(sp n )-H Activations, 26 Other Oxidations and Oxidative Processes, 26 Reduction of Carbonyl Compounds, 27 Miscellaneous Cyclizations, 28 Other Reactions, 31 References, 34 Organic Reaction Mechanisms 2019, First Edition. Edited by M. G. Moloney. © 2023 John Wiley & Sons Ltd. Published 2023 by John Wiley & Sons Ltd.
eBook - PDFOrganic Reaction Mechanisms 2017
An annual survey covering the literature dated January to December 2017
- A. C. Knipe, Mark G. Moloney, A. C. Knipe, Mark G. Moloney(Authors)
- 2020(Publication Date)
- Wiley(Publisher)
1 1 Reactions of Aldehydes and Ketones and their Derivatives S. R. Hussaini Department of Chemistry and Biochemistry, The University of Tulsa, Tulsa, OK, United States CHAPTER MENU Formation and Reactions of Acetals and Related Species, 2 Reactions of Glucosides, 3 Reactions of Ketenes, 7 Formation and Reactions of Nitrogen Derivatives, 8 Imines: General, Synthesis, and Iminium Chemistry, 8 Mannich, Mannich-type, and nitro-Mannich Reactions, 11 Other ‘Name’ Reactions of Imines, 11 Alkylations, 11 Miscellaneous Additions to Imines, 14 Oxidation and Reduction of Imines, 14 Other Reactions of Imines, 17 Oximes, Hydrazones, and Related Species, 23 C–C Bond Formation and Fission: Aldol and Related Reactions, 30 Asymmetric Aldol Reactions, 31 The Mukaiyama Aldol, 31 Other Aldol and Aldol-type Reactions, 33 Alkynylations, 36 Michael Addition and Miscellaneous Condensations, 36 Other Addition Reactions, 43 Arylations, 44 Addition of Other Organometallics, including Grignards, 44 The Wittig, Julia-Kocienski, Peterson, and Other Olefinations, 44 Hydrophosphonylation, Hydroboration, and Addition of Isocyanide, 46 Miscellaneous Additions, 46 Enolization, Reactions of Enolates, and Related Reactions, 50 𝛼 -Substitutions, 50 Oxidation and Reduction of Carbonyl Compounds, 51 Oxidation of Aldehydes to Amides and Nitriles, 51 Decarbonylation Reactions, 51 Miscellaneous Oxidative Processes, 53 Stereoselective Reduction Reactions, 57 Other Reactions, 59 References, 59 Organic Reaction Mechanisms 2017, First Edition. Edited by A. C. Knipe and M. G. Moloney. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd. 2 Organic Reaction Mechanisms 2017 Formation and Reactions of Acetals and Related Species Novel nitrated [6,6,6]-tricyclic acetal or ketals are prepared by an intramolecular annulation of o -carbonyl allylbenzenes. The proposed mechanism involves olefinic nitration, bis-cyclization, and tautomerization, followed by another nitration.
eBook - PDF- H. Stephen Stoker(Author)
- 2015(Publication Date)
- Cengage Learning EMEA(Publisher)
C O O O B O O O CH 2 CH 2 CH 2 O CH 3 CH 3 Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 132 CHAPTER 4 Aldehydes and Ketones Aldehydes and ketones are related to alcohols in the same manner that alkenes are related to alkanes. Removal of hydrogen atoms from each of two adjacent carbon atoms in an alkane produces an alkene. In a like manner, removal of a hydrogen atom from the ! OH group of an alcohol and from the carbon atom to which the hydroxyl group is attached produces a carbonyl group (see Figure 4-1). Figure 4-1 Aldehydes and ketones are related to alcohols in the same manner that alkenes are related to alkanes; removal of two hydrogen atoms produces a double bond. H O C O C – 2 H H Alcohol Aldehyde or ketone Alkane Alkene H C C C C – 2 H H a b Formation of a carbon– oxygen double bond Formation of a carbon– carbon double bond 1. In an aldehyde the carbonyl group a. is always located at the end of the carbon chain b. may be at the end of or in an interior position on the carbon chain c. is always located in an interior position on the carbon chain d. no correct response 2. In a ketone the carbonyl group a. is always located at the end of the carbon chain b. may be at the end of or in an interior position on the carbon chain c. is always located in an interior position on the carbon chain d. no correct response 3. Which of the following is a generalized linear structural designation for an aldehyde? a. RCOH b. RCHO c. RCOR d. no correct response Section 4-3 Quick Quiz Answers: 1.
eBook - PDFOrganic Reaction Mechanisms 2016
An annual survey covering the literature dated January to December 2016
- A. C. Knipe(Author)
- 2019(Publication Date)
- Wiley(Publisher)
CHAPTER 1 Reactions of Aldehydes and Ketones and Their Derivatives B. A. Murray Department of Science, Technological University of Dublin (TU Dublin), Dublin, Ireland Formation and Reactions of Acetals and Related Species . . . . . . . . . . . . . . 2 Reactions of Glucosides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Reactions of Ketenes and Related Cumulenes . . . . . . . . . . . . . . . . . . . . . 7 Formation and Reactions of Nitrogen Derivatives . . . . . . . . . . . . . . . . . . . 8 Imines: Synthesis, and General and Iminium Chemistry . . . . . . . . . . . . . 8 Mannich, Mannich-type, and Nitro-Mannich Reactions . . . . . . . . . . . . . 10 Other ‘Name’ Reactions of Imines . . . . . . . . . . . . . . . . . . . . . . . . 14 Stereoselective Hydrogenation of Imines, and Other Reductive Processes . . . . 15 Stereoselective Allyl-, Aryl-, Alkenyl-, and Alkynyl-ations of Imines . . . . . . 17 Other Stereoselective Reactions of Imines . . . . . . . . . . . . . . . . . . . . 18 Other Reactions of Imines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Oximes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Hydrazones and Related Species . . . . . . . . . . . . . . . . . . . . . . . . . 24 C–C Bond Formation and Fission: Aldol and Related Reactions . . . . . . . . . . 27 Reviews of Aldols, and General Reviews of Asymmetric Catalysis . . . . . . . 27 Asymmetric Aldols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 The Mukaiyama Aldol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 The Morita–Baylis–Hillman Reaction . . . . . . . . . . . . . . . . . . . . . . 31 Other Aldol-type Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Allylation and Related Reactions . . . . . . . . . . . . . . . . . . . . . . . . . 33 Alkynylations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 The Benzoin and Stetter Reactions . .
eBook - PDFGeneral, Organic, and Biological Chemistry
An Integrated Approach
- Kenneth W. Raymond(Author)
- 2012(Publication Date)
- Wiley(Publisher)
When naming aldehydes and ketones according to the IUPAC rules, the carbonyl group (C “ O) must be part of the parent chain, which is numbered from the end nearer this group. Since the carbonyl carbon atom of an aldehyde is always in position number 1, its position is not specified in the name. For ketones, however, the position of the carbonyl carbon is given, unless the molecule is small enough that there is no question as to carbonyl placement. Parent chains are named by dropping the final “e” from the name of the corresponding hydrocarbon and adding “al” for aldehydes or “one” for ketones (Figure 9.7). The common names of ketones are formed by placing “ketone” after the names of the alkyl groups attached to the carbonyl carbon atom. For aldehydes and for some ketones, other common names are assigned. Three important ones to know are formaldehyde (methanal), acetaldehyde (ethanal), and acetone (propanone) (Figure 9.7). you have decided on the reaction type, think about the different rules that apply: How do different types of alcohols respond to oxidation and which is the major alkene product expected from dehydration? SOLUTION a. K 2 Cr 2 O 7 CH 3 CH 2 CH 2 OH CH 3 CH 2 C¬OH O ‘ b. K 2 Cr 2 O 7 CH 3 CHCH 3 OH ƒ CH 3 CCH 3 O ‘ c. H + heat CH 3 CH 2 CH 2 OH CH 3 CH“CH 2 d. H + heat CH 3 CH“CH 2 CH 3 CHCH 3 OH ƒ PRACTICE PROBLEM 9.5 Draw the organic product (if any) expected from each reaction. a. K 2 Cr 2 O 7 OH CH 3 d. H + heat OH CH 3 b. K 2 Cr 2 O 7 CH 2 OH e. CH 2 OH H + heat c. K 2 Cr 2 O 7 OH CH 3 f. OH CH 3 H + heat 9.4 Aldehydes and Ketones 345 Aldehydes and ketones have much lower boiling points than alcohols with a similar molecular weight. Ethanol, for example, has a boiling point of 78.5°C, while ethanal has a boiling point of 20°C (Table 9.2). The difference in boiling points is due to dif- ferences in how the molecules are attracted to one another.
eBook - PDFOrganic Reaction Mechanisms 1966
An annual survey covering the literature dated December 1965 through November 1966
- B. Capon, M. J. Perkins, C. W. Rees, B. Capon, M. J. Perkins, C. W. Rees(Authors)
- 2008(Publication Date)
- Wiley-Interscience(Publisher)
CHAPTER 11 Reactions of Aldehydes and Ketones and their Derivatives’ Formation and Reactions of Acetals and Ketals Replacement of the hydrogen at C(z) of 2-phenyl-1,3-dioxolanby a methyl or ethyl group results in a 5- or 25-fold decrease in the rate of the acid-catalysed hydrolysis in 50% dioxan-water at 30°.2Similarreplacementsin benzaldehyde n n n n O x 0 O x 0 O x 0 O x 0 Ph H Ph Me Ph Et Ph Ph kz 1. mole-1 min-1 25.4 5.00 1.04 0.216 diethyl acetal result in 33- and 9-fold rate increases. The entropies of activation for the hydrolyses of the dioxolans are negative (ca.-9 e.u.) and the slower rates of the 2-methyl-2-phenyl- and 2-ethyl-2-phenyl than of the 2-phenyl compound are the result of higher energies of activation. It was also found that 2,2-diphenyldioxolan is hydrolysed about 120 times more slowly than 2-phenyldioxolan which is to be compared with the 20-fold slower rate of hydrolysis of benzophenonediethyl ketal than of benzaldehyde diethyl acetaL3 A possible explanation is that the transition state resembles the protonated substrate so that conjugation by substituents is relatively unimportant. Alternatively, a steric effect may be important. This could be either steric inhibition of resonance between the phenyl group and the carbonium ion centre3 or an effect arising from the transition state’s having oxonium ion character which requires C(z), 0(3), C(4), and the bonds to C(z) to be coplanar.4a In our opinion the latter explanation is the more likely. It has been suggested that the rate-dependence on glycerol content of water-glycerol mixtures may be used as a criterion for distinguishingbetween A-1 and A-2 mechanisms in acid-catalysed reactions.4b One of the A-1 1 An extensive monograph on Reactions of Aldehydes and Ketones has been published: “Chem- istry of the Carbonyl Group”, S. Patai, ed., John Wiley, London, New York, Sydney, 1966. 2 T. H. Fife and L. Hagopian, J. Org. Chem., 31, 1772 (1966). 3 M. M. Kreevoy and R. W. Taft, J . Am. Chem. ~ o c .
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