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Synthesis Of Ketones From Carboxylic Acids

One-pot Synthesis Of Ketones From Carboxylic Acids And Grignard Reagents Using N,n-diphenyl-p-methoxyphenylchloromethyleniminium Chloride

One-pot Synthesis Of Ketones From Carboxylic Acids And Grignard Reagents Using N,n-diphenyl-p-methoxyphenylchloromethyleniminium Chloride

N,N-Diphenyl-p-methoxyphenylchloromethyleniminium chloride is found to be an effective condensation reagent of carboxylic acids and Grignard reagents under mild conditions to afford the corresponding ketones in high yields. View more articles Continue reading >>

Aldehydes And Ketones

Aldehydes And Ketones

Nature of The Carbonyl Group The carbonyl group consists of a carbon double bonded to an oxygen. >C=O Similar to alkenes - >C=C< >C=O - carbon is sp2 hybridized - 120o bond angles - planar about the double bond Polar d+ d- + - >C==O « >C—O - C is electrophilic - O is nucleophilic Classification of Carbonyl Compounds by R- and Y- All carbonyl compounds contain an acyl group , RCO- , bonded to another residue, -Y. R- = alkyl, aryl alkenyl or alkynyl Y- = C, H, O, N, S, halogen, or other atom Aldehyde: Y = H Ketone: Y = R group Classification of Carbonyl Compounds by Rxn Types A. Y = non-leaving groups. (e.g. aldehydes and ketones) B. Y = leaving groups. (e.g. -OR, -NR2, -Cl) Aldehydes: R-CHO Ar-CHO Ketones: R-COR' Ar-COR Ar-COAr' Aldehyde Nomenclature 1. Identify the longest continuous chain of carbons with the carbonyl carbon as part of the chain. 2. Assign priority (number the carbon chain) so that the carbonyl (acyl) carbon is always #1. In nomenclature the carbonyl has higher priority than the hydroxyl group. 3. Locate and identify alphabetically the branched groups by prefixing the carbon number it is attached to. If more than one of the same type of branched group is involved use the Greek prefixes di for 2, tri for three, etc. 4. After identifying the name, number and location of each branched group, use the alkane name corresponding to the number of carbons in the continuous chain. 5. Drop the "e" and add the characteristic IUPAC ending for all aldehydes, "al". 6. Alkenals involving Pi bonding will require that the Pi bond is located but the ending will still be "al". 7. If the -CHO group is attached to a ring the suffix -carbaldehyde is used. Systematic name (common name) Systematic name (common name) Methanal (formaldehyde) 3-bromo-5-methylhexanal Ethanal (ac Continue reading >>

Ketone

Ketone

Not to be confused with ketone bodies. Ketone group Acetone In chemistry, a ketone (alkanone) /ˈkiːtoʊn/ is an organic compound with the structure RC(=O)R', where R and R' can be a variety of carbon-containing substituents. Ketones and aldehydes are simple compounds that contain a carbonyl group (a carbon-oxygen double bond). They are considered "simple" because they do not have reactive groups like −OH or −Cl attached directly to the carbon atom in the carbonyl group, as in carboxylic acids containing −COOH.[1] Many ketones are known and many are of great importance in industry and in biology. Examples include many sugars (ketoses) and the industrial solvent acetone, which is the smallest ketone. Nomenclature and etymology[edit] The word ketone is derived from Aketon, an old German word for acetone.[2][3] According to the rules of IUPAC nomenclature, ketones are named by changing the suffix -ane of the parent alkane to -anone. The position of the carbonyl group is usually denoted by a number. For the most important ketones, however, traditional nonsystematic names are still generally used, for example acetone and benzophenone. These nonsystematic names are considered retained IUPAC names,[4] although some introductory chemistry textbooks use systematic names such as "2-propanone" or "propan-2-one" for the simplest ketone (CH3−CO−CH3) instead of "acetone". The common names of ketones are obtained by writing separately the names of the two alkyl groups attached to the carbonyl group, followed by "ketone" as a separate word. The names of the alkyl groups are written alphabetically. When the two alkyl groups are the same, the prefix di- is added before the name of alkyl group. The positions of other groups are indicated by Greek letters, the α-carbon being th Continue reading >>

The Haloform Reaction: Conversion Of Methyl Ketones To Carboxylic Acids

The Haloform Reaction: Conversion Of Methyl Ketones To Carboxylic Acids

So I understand that the haloform reaction when using Iodine provides a nifty way to identify methyl ketones because the LG ‘CI3 precipates as a yellow solid in the form of Iodoform; I also understand that secondary methyl alcohols are oxidized by I2 in a radical-led oxidation rxn to a methyl ketone, which obviously goes through a subsequent reaction with I2. However, why do primary alcohols such as ethanol or propanol not react with I2? Would methanol react? My book does not expand anymore than just that I2 will react with methyl ketones and secondary methyl alcohols. Thanks! James Organic Chemistry 2 builds on the concepts from Org 1 and introduces a lot of new reactions. Here is an index of posts for relevant topics in Organic Chemistry 2: [Hint – searching for something specific? Try CNTRL-F] General Posts About Organic Chemistry 2 Oxidation And Reduction Alcohols, Ethers, And Epoxides Conjugation, Dienes and Pericyclic Reactions Aromaticity and Aromatic Reactions Aldehydes and Ketones Carboxylic Acid Derivatives General Posts Concerning Organic Chemistry 2 Oxidation And Reduction Alcohols, Epoxides, And Ethers Alcohols (1) Nomenclature And Properties How To Make Alcohols More Reactive Alcohols (3) Acidity And Basicity The Williamson Ether Synthesis Williamson Ether Synthesis: Planning Synthesis of Ethers (2) – Back To The Future! Ether Synthesis Via Alcohol And Acid Cleavage Of Ethers With Acid Epoxides – The Outlier Of The Ether Family Opening Of Epoxides With Acid Opening Of Epoxides With Base Making Alkyl Halides From Alcohols Tosylates And Mesylates PBr3 And SOCl2 Elimination Reactions Of Alcohols Elimination Of Alcohols To Alkenes With POCl3 Alcohol Oxidation: “Strong” And “Weak” Oxidants Demystifying Alcohol Oxidations Intramolecular Reactions Continue reading >>

Synthesis Of Aldehydes & Ketones

Synthesis Of Aldehydes & Ketones

Aldehydes and ketones can be prepared using a wide variety of reactions. Although these reactions are discussed in greater detail in other sections, they are listed here as a summary and to help with planning multistep synthetic pathways. Please use the appropriate links to see more details about the reactions. Continue reading >>

Aldehydes, Ketones, Carboxylic Acids, And Esters

Aldehydes, Ketones, Carboxylic Acids, And Esters

Learning Objectives By the end of this section, you will be able to: Describe the structure and properties of aldehydes, ketones, carboxylic acids and esters Another class of organic molecules contains a carbon atom connected to an oxygen atom by a double bond, commonly called a carbonyl group. The trigonal planar carbon in the carbonyl group can attach to two other substituents leading to several subfamilies (aldehydes, ketones, carboxylic acids and esters) described in this section. Aldehydes and Ketones Both aldehydes and ketones contain a carbonyl group, a functional group with a carbon-oxygen double bond. The names for aldehyde and ketone compounds are derived using similar nomenclature rules as for alkanes and alcohols, and include the class-identifying suffixes –al and –one, respectively: In an aldehyde, the carbonyl group is bonded to at least one hydrogen atom. In a ketone, the carbonyl group is bonded to two carbon atoms: In both aldehydes and ketones, the geometry around the carbon atom in the carbonyl group is trigonal planar; the carbon atom exhibits sp2 hybridization. Two of the sp2 orbitals on the carbon atom in the carbonyl group are used to form σ bonds to the other carbon or hydrogen atoms in a molecule. The remaining sp2 hybrid orbital forms a σ bond to the oxygen atom. The unhybridized p orbital on the carbon atom in the carbonyl group overlaps a p orbital on the oxygen atom to form the π bond in the double bond. Like the C=O bond in carbon dioxide, the C=O bond of a carbonyl group is polar (recall that oxygen is significantly more electronegative than carbon, and the shared electrons are pulled toward the oxygen atom and away from the carbon atom). Many of the reactions of aldehydes and ketones start with the reaction between a Lewis base and Continue reading >>

Synthesis Of Ketones

Synthesis Of Ketones

Like aldehydes, ketones can be prepared in a number of ways. The following sections detail some of the more common preparation methods: the oxidation of secondary alcohols, the hydration of alkynes, the ozonolysis of alkenes, Friedel‐Crafts acylation, the use of lithium dialkylcuprates, and the use of a Grignard reagent. The oxidation of secondary alcohols to ketones may be carried out using strong oxidizing agents, because further oxidation of a ketone occurs with great difficulty. Normal oxidizing agents include potassium dichromate (K 2Cr 2O 7) and chromic acid (H 2CrO 4). The conversion of 2‐propanol to 2‐propanone illustrates the oxidation of a secondary alcohol. The addition of water to an alkyne leads to the formation of an unstable vinyl alcohol. These unstable materials undergo keto‐enol tautomerization to form ketones. The hydration of propyne forms 2‐propanone, as the following figure illustrates. When one or both alkene carbons contain two alkyl groups, ozonolysis generates one or two ketones. The ozonolysis of 1,2‐dimethyl propene produces both 2‐propanone (a ketone) and ethanal (an aldehyde). Friedel‐Crafts acylations are used to prepare aromatic ketones. The preparation of acetophenone from benzene and acetyl chloride is a typical Friedel‐Crafts acylation. The addition of a lithium dialkylcuprate (Gilman reagent) to an acyl chloride at low temperatures produces a ketone. This method produces a good yield of acetophenone. Hydrolysis of the salt formed by reacting a Grignard reagent with a nitrile produces good ketone yields. For example, you can prepare acetone by reacting the Grignard reagent methyl magnesium bromide (CH 3MgBr) with methyl nitrile (CH 3C&tbond;N). Continue reading >>

Direct Easy Synthesis Of Ketones From Carboxylic Acids And Chlorinated Compounds†

Direct Easy Synthesis Of Ketones From Carboxylic Acids And Chlorinated Compounds†

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Synthesis Of Carboxylic Acids

Synthesis Of Carboxylic Acids

Most of the methods for the synthesis of carboxylic acids can be put into one of two categories: (1) hydrolysis of acid derivatives and (2) oxidation of various compounds. All acid derivatives can be hydrolyzed (cleaved by water) to yield carboxylic acids; the conditions required range from mild to severe, depending on the compound involved. The easiest acid derivatives to hydrolyze are acyl chlorides, which require only the addition of water. Carboxylic acid salts are converted to the corresponding acids instantaneously at room temperature simply on treatment with water and a strong acid such as hydrochloric acid (shown as H+ in the equations above). Carboxylic esters, nitriles, and amides are less reactive and typically must be heated with water and a strong acid or base to give the corresponding carboxylic acid. If a base is used, a salt is formed instead of the carboxylic acid, but the salt is easily converted to the acid by treatment with hydrochloric acid. Of these three types of acid derivatives, amides are the least reactive and require the most vigorous treatment (i.e., higher temperatures and more prolonged heating). Under milder conditions, nitriles can also be partially hydrolyzed, yielding amides: RCN → RCONH2. The oxidation of primary alcohols is a common method for the synthesis of carboxylic acids: RCH2OH → RCOOH. This requires a strong oxidizing agent, the most common being chromic acid (H2CrO4), potassium permanganate (KMnO4), and nitric acid (HNO3). Aldehydes are oxidized to carboxylic acids more easily (by many oxidizing agents), but this is not often useful, because the aldehydes are usually less available than the corresponding acids. Also important is the oxidation of alkyl side chains of aromatic rings by strong oxidizing agents such as chrom Continue reading >>

(cf3co)2o/cf3so3h-mediated Synthesis Of 1,3-diketones From Carboxylic Acids And Aromatic Ketones

(cf3co)2o/cf3so3h-mediated Synthesis Of 1,3-diketones From Carboxylic Acids And Aromatic Ketones

Go to: Results and Discussion Initially, an unusual transformation of the β-phenylpropionic acids was observed by us in a TFAA/TfOH/CH2Cl2 system (Table 1), which gave the impulse for this research. Surprisingly, it turned out that β-phenylpropionic acid (1a) in a TFAA/CH2Cl2 medium in the presence of TfOH (0.25 equiv, Table 1, entry 1) gave 2-(β-phenylpropionyl)-1-indanone (3а) in 51% yield as the major product, even though we expected 1-indanone (2а, <2%). When 0.5 equiv of TfOH was applied, 3а and 2a were obtained in 75 and 16% yield, respectively (Table 1, entry 2). Evidently, in this reaction, 1-indanone (2а), which was initially formed as the result of an intramolecular cyclization of 1a, underwent a further acylation with the formation of 1,3-diketone 3a. In contrast, γ-phenylbutanoic acid (1c) was quantitatively transformed only to the tetralone 2с (Table 1, entries 10 and 11). The acid-catalyzed cyclization of 3-arylpropanoic and 4-arylbutanoic acids to 1-indanones and 1-tetralones is well-known [12–18], but it appears that the further acylation and β-diketone formation has not been reported yet. While the use of acyl trifluoroacetates, generated in situ from a carboxylic acid and TFAA, for the aromatic acylation catalyzed by acid (H3PO4 [19–22] or TfOH [23–25]) has been reported, the 1,3-diketone formation has not been observed yet. We concluded that in the work of reference [25], an apparently larger quantity of the super acidic TfOH was employed (4 equiv vs 0.25–1.5 equiv in our work), which possibly slowed down the reaction of ketone acylation. This is corroborated in the case of phenylpropionic acid 1а. Here, the yield of the diketone 3a decreased with an increase of the quantity of TfOH, whereas the yield of 1-indanone (2a) increased an Continue reading >>

One-pot Synthesis Of Aldehydes Or Ketones From Carboxylic Acids Via In Situ Generation Of Weinreb Amides Using The Deoxo-fluor Reagent

One-pot Synthesis Of Aldehydes Or Ketones From Carboxylic Acids Via In Situ Generation Of Weinreb Amides Using The Deoxo-fluor Reagent

A one-pot, high yield conversion of carboxylic acids to the corresponding aldehydes and ketones is described. The highlight of this methodology is the in situ generation of Weinreb amides with the Deoxo-Fluor reagent, which undergo nucleophilic reaction with DIBAL-H and Grignard reagents. Continue reading >>

Reactions At The Α-carbon

Reactions At The Α-carbon

Many aldehydes and ketones were found to undergo electrophilic substitution at an alpha carbon. These reactions, which included halogenation, isotope exchange and the aldol reaction, take place by way of enol tautomer or enolate anion intermediates, a characteristic that requires at least one hydrogen on the α-carbon atom. In this section similar reactions of carboxylic acid derivatives will be examined. Formulas for the corresponding enol and enolate anion species that may be generated from these derivatives are drawn in the following diagram. Acid-catalyzed alpha-chlorination and bromination reactions proceed more slowly with carboxylic acids, esters and nitriles than with ketones. This may reflect the smaller equilibrium enol concentrations found in these carboxylic acid derivatives. Nevertheless, acid and base catalyzed isotope exchange occurs as expected; some examples are shown in equations #1 and #2 below. The chiral alpha-carbon in equation #2 is racemized in the course of this exchange, and a small amount of nitrile is hydrolyzed to the corresponding carboxylic acid. Acyl halides and anhydrides are more easily halogenated than esters and nitriles, probably because of their higher enol concentration. This difference may be used to facilitate the alpha-halogenation of carboxylic acids. Thus, conversion of the acid to its acyl chloride derivative is followed by alpha-bromination or chlorination, and the resulting halogenated acyl chloride is then hydrolyzed to the carboxylic acid product. This three-step sequence can be reduced to a single step by using a catalytic amount of phosphorus tribromide or phosphorus trichloride, as shown in equation #3. This simple modification works well because carboxylic acids and acyl chlorides exchange functionality as the reactio Continue reading >>

A New Practical Ketone Synthesis Directly From Carboxylic Acids: First Application Of Coupling Reagents In Palladium Catalysis

A New Practical Ketone Synthesis Directly From Carboxylic Acids: First Application Of Coupling Reagents In Palladium Catalysis

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On The Reaction Between Methyllithium And Carboxylic Acids

On The Reaction Between Methyllithium And Carboxylic Acids

In 1933, Gilman showed that on carbonation phenyllithium yielded 70% benzophenone and no benzoic acid, which is the main product on carbonation of the corresponding magnesium compound. They found that the reason for the high yield of ketone was the higher reactivity of the organolithium compound. If an aryllithium compound was allowed to react with carbon dioxide at temperatures between -50°C and -80°C the following reaction occurred: RLi + CO2 RCOOLi At a higher temperature (room temperature) another reaction took place. To the lithium salt of ArCOOH was added one mole of aryllithium, and a dilithium salt of a dihydroxymethane was obtained, which on hydrolysis yielded a ketone in accordance with the following general reaction: Only in one case, hitherto, has any comparison been made between the use of the free acid or its lithium salt: In the case of benzophenone Gilman and van Ess have made two syntheses. One started with the lithium benzoate, which was allowed to react with one mole of phenyllithium, and was found to give a 70% yield of ketone and no tertiary alcohol; the second experiment started with benzoic acid and two moles of phenyllithium and yielded 37.2% of ketone and 14.1% of triphenylcarbinol. Two possible explanations are given for the formation of the tertiary alcohol. The first is that benzoic acid is dehydrated by phenyllithium to give benzoic anhydride. This would react with one mole of phenyllithium to give lithium benzoate and "free" benzophenone, which would enter the ordinary reaction of a ketone yielding triphenylcarbinol: 2 C6H5COOH + 2 C6H5Li (C6H5CO)2O (C6H5CO)2O + C6H5Li (C6H5)2CO + C6H5COOLi (C6H5)2CO + C6H5Li (C6H5)3COLi -> (C6H5)3COH Another explanation is suggested, in which the phenyllithium is supposed to be added directly to the carb Continue reading >>

Synthesis Of Aldehydes And Ketones

Synthesis Of Aldehydes And Ketones

Name Reactions Fukuyama Coupling Grignard Reaction Grignard Reaction Seebach Umpolung Stetter Synthesis Recent Literature Carboxylic acids were converted directly in good yields into ketones using excess alkyl cyanocuprates (R2CuLi•LiCN). A substrate with a stereocenter α to the carboxylic acid was converted with very little loss of enantiomeric purity. A variety of functional groups were tolerated including aryl bromides. This direct transformation involves a relatively stable copper ketal tetrahedral intermediate. D. T Genna, G. H. Posner, Org. Lett., 2011, 13, 5358-5361. Unsymmetrical dialkyl ketones can be prepared by the nickel-catalyzed reductive coupling of carboxylic acid chlorides or (2-pyridyl)thioesters with alkyl iodides or benzylic chlorides. Various functional groups are tolerated, including common nitrogen protecting groups and C-B bonds. Even hindered ketones flanked by tertiary and secondary centers can be formed. A. C. Wotal, D. J. Weix, Org. Lett., 2012, 14, 1363-1365. N-acylazetidines are bench-stable, readily available amide acylating reagents, in which the reactivity is controlled by amide pyramidalization and strain of the four-membered ring. A general and highly chemoselective synthesis of ketones by the addition of organometallics to N-acylazetidines via stable tetrahedral intermediates offers wide substrate scope and exquisite selectivity for the ketone products. C. Liu, M. Achtenhagen, M. Szostak, Org. Lett., 2016, 18, 2375-2378. A range of unsymmetrical ketones has been prepared in good yields from aldehydes in one simple synthetic operation by addition of organolithium compounds followed by an oxidation using N-tert-butylphenylsulfinimidoyl chloride. J. J. Crawford, K. W. Hederson, W. J. Kerr, Org. Lett., 2006, 8, 5073-5076. Visible light Continue reading >>

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