The Cannizzaro reaction, named after its discoverer Stanislao Cannizzaro, is a chemical reaction that involves the base-induced disproportionation of two molecules of a non-enolizable aldehyde to give a primary alcohol and a carboxylic acid
The Cannizzaro reaction is a chemical reaction discovered by Italian chemist Stanislao Cannizzaro in 1853. It involves the disproportionation of an aldehyde in the presence of a strong base. One aldehyde molecule is oxidized to the corresponding carboxylic acid, while another is reduced to the alcohol. The reaction allows the conversion of aldehydes lacking an alpha hydrogen to the corresponding acid and alcohol. It has various applications in organic synthesis and is an important reaction in chemistry.
The Cannizzaro reaction is a disproportionation reaction discovered by Italian chemist Stanislao Cannizzaro in 1853. In the reaction, an aldehyde without an alpha hydrogen undergoes a base-catalyzed reaction in the presence of a strong base like potassium hydroxide or sodium hydroxide and heat to produce an alcohol and a carboxylic acid as products. The reaction allows for the conversion of aldehydes into mixtures of carboxylic acids and alcohols.
The document discusses the Cannizzaro reaction, which is the disproportionation of aldehydes in basic conditions to produce an alcohol and a carboxylic acid. It was discovered by Stanislao Cannizzaro in 1853. The reaction requires an aromatic or aliphatic aldehyde without alpha hydrogens and a strong base like potassium hydroxide. The mechanism involves deprotonation of the aldehyde followed by hydride transfer to another aldehyde molecule. Examples and limitations of the reaction are provided. Variations like the crossed and intramolecular Cannizzaro reactions are also described.
The Wittig reaction involves reacting an aldehyde or ketone with a triphenylphosphonium ylide to form an alkene and triphenylphosphine oxide. The reaction proceeds through betaine and oxaphosphetane intermediates. The stereochemistry of the product can be controlled by the reactants and conditions. Similar reactions are the Horner and Horner-Emmons-Wadsworth reactions, which use different reagents. The Wittig reaction is one of the main methods for synthesizing alkenes from carbonyl compounds.
IMPORTANT NAMED REACTIONS in Organic synthesis with Introduction, General Mechanism, and their synthetic application covering more than 20 named reactions in it.
The Cannizaro reaction involves the base-induced disproportionation of two molecules of a non-enolizable aldehyde to yield a carboxylic acid and a primary alcohol. It was discovered by Stanislao Cannizaro. The reaction begins with hydroxide attack on the carbonyl carbon to form an unstable dianion intermediate. This releases a hydride anion to reduce another aldehyde molecule to an alcohol. The dianion is then converted to a carboxylate anion and carboxylic acid product after acid workup. The Cannizaro reaction is limited to aldehydes without alpha hydrogens, as those favor the aldol condensation reaction instead.
Quinoline and isoquinoline- heterocyclic chemistry- pharmacyAkhil Nagar
This document discusses the properties, synthesis, and reactions of quinoline and isoquinoline. Quinoline and isoquinoline are aromatic and undergo nucleophilic substitution reactions readily. Key synthesis methods discussed include the Skraup, Doebner-Miller, Friedlander, Bischler-Napieralski, Pictet-Gams, and Pomeranz-Fritsch reactions. The document also outlines various electrophilic addition, substitution, reduction, oxidation, and nucleophilic substitution reactions that quinoline and isoquinoline undergo. Finally, some medicinal uses of quinoline and isoquinoline are mentioned.
The document summarizes the Birch reduction reaction, which involves the reduction of aromatic rings with sodium, potassium, or lithium in liquid ammonia or amines in the presence of alcohol. This adds hydrogen to the 1 and 4 positions of the aromatic ring to form an unconjugated diene. The summary discusses the reaction reagents (alkali metals and alcohol or ammonia solvent), mechanism (electron transfer and proton addition), products (1,4-dihydro derivatives), and applications (synthesis of cyclohexenones, hydrocarbons from naphthalene and anthracene). It also acknowledges the professors who provided guidance on the topic.
The Cannizzaro reaction is a chemical reaction discovered by Italian chemist Stanislao Cannizzaro in 1853. It involves the disproportionation of an aldehyde in the presence of a strong base. One aldehyde molecule is oxidized to the corresponding carboxylic acid, while another is reduced to the alcohol. The reaction allows the conversion of aldehydes lacking an alpha hydrogen to the corresponding acid and alcohol. It has various applications in organic synthesis and is an important reaction in chemistry.
The Cannizzaro reaction is a disproportionation reaction discovered by Italian chemist Stanislao Cannizzaro in 1853. In the reaction, an aldehyde without an alpha hydrogen undergoes a base-catalyzed reaction in the presence of a strong base like potassium hydroxide or sodium hydroxide and heat to produce an alcohol and a carboxylic acid as products. The reaction allows for the conversion of aldehydes into mixtures of carboxylic acids and alcohols.
The document discusses the Cannizzaro reaction, which is the disproportionation of aldehydes in basic conditions to produce an alcohol and a carboxylic acid. It was discovered by Stanislao Cannizzaro in 1853. The reaction requires an aromatic or aliphatic aldehyde without alpha hydrogens and a strong base like potassium hydroxide. The mechanism involves deprotonation of the aldehyde followed by hydride transfer to another aldehyde molecule. Examples and limitations of the reaction are provided. Variations like the crossed and intramolecular Cannizzaro reactions are also described.
The Wittig reaction involves reacting an aldehyde or ketone with a triphenylphosphonium ylide to form an alkene and triphenylphosphine oxide. The reaction proceeds through betaine and oxaphosphetane intermediates. The stereochemistry of the product can be controlled by the reactants and conditions. Similar reactions are the Horner and Horner-Emmons-Wadsworth reactions, which use different reagents. The Wittig reaction is one of the main methods for synthesizing alkenes from carbonyl compounds.
IMPORTANT NAMED REACTIONS in Organic synthesis with Introduction, General Mechanism, and their synthetic application covering more than 20 named reactions in it.
The Cannizaro reaction involves the base-induced disproportionation of two molecules of a non-enolizable aldehyde to yield a carboxylic acid and a primary alcohol. It was discovered by Stanislao Cannizaro. The reaction begins with hydroxide attack on the carbonyl carbon to form an unstable dianion intermediate. This releases a hydride anion to reduce another aldehyde molecule to an alcohol. The dianion is then converted to a carboxylate anion and carboxylic acid product after acid workup. The Cannizaro reaction is limited to aldehydes without alpha hydrogens, as those favor the aldol condensation reaction instead.
Quinoline and isoquinoline- heterocyclic chemistry- pharmacyAkhil Nagar
This document discusses the properties, synthesis, and reactions of quinoline and isoquinoline. Quinoline and isoquinoline are aromatic and undergo nucleophilic substitution reactions readily. Key synthesis methods discussed include the Skraup, Doebner-Miller, Friedlander, Bischler-Napieralski, Pictet-Gams, and Pomeranz-Fritsch reactions. The document also outlines various electrophilic addition, substitution, reduction, oxidation, and nucleophilic substitution reactions that quinoline and isoquinoline undergo. Finally, some medicinal uses of quinoline and isoquinoline are mentioned.
The document summarizes the Birch reduction reaction, which involves the reduction of aromatic rings with sodium, potassium, or lithium in liquid ammonia or amines in the presence of alcohol. This adds hydrogen to the 1 and 4 positions of the aromatic ring to form an unconjugated diene. The summary discusses the reaction reagents (alkali metals and alcohol or ammonia solvent), mechanism (electron transfer and proton addition), products (1,4-dihydro derivatives), and applications (synthesis of cyclohexenones, hydrocarbons from naphthalene and anthracene). It also acknowledges the professors who provided guidance on the topic.
Favorskii rearrangement is one the important reactions in organic chemistry. Let us have some prior understanding of its mechanism and its applications.
The document summarizes the Darzen condensation reaction, which involves the formation of α,β-epoxy esters (glycidic esters) from aldehydes/ketones and α-halo esters under basic conditions. It provides background on the reaction's history and development. The reaction mechanism proceeds through an initial aldol reaction followed by epoxide ring formation. Examples and applications in multi-step syntheses are described. Limitations include the reaction failing for some aldehydes due to self-condensation and difficultly obtaining high, sole product yields needed for kinetic studies.
The benzoin condensation is a reaction between two molecules of benzaldehyde catalyzed by cyanide ions to form benzoin. It was first reported in 1832 by Liebig and Wöhler. It involves a cyanide ion forming a cyanohydrin intermediate with benzaldehyde, followed by a condensation reaction between the cyanohydrin and another benzaldehyde molecule. This forms benzoin along with the removal of cyanide ions. Benzoin condensation is useful for organic synthesis and producing polymers.
This document presents information about the Perkin reaction, which was discovered in the 19th century by English chemist William Henry Perkin. The Perkin reaction is an aldol condensation that converts an aromatic aldehyde and an acid anhydride to an alpha beta unsaturated cinnamic acid. It involves a four step mechanism - abstraction of alpha hydrogen from the acid anhydride, attack of the carbanion on the carbonyl carbon of benzaldehyde, an intramolecular acetyl shift, and loss of the acetate ion to form the unsaturated carboxylic acid product. The Perkin reaction is used to synthesize cinnamic acids, phytoestrogens, stilbenes, and resver
The document summarizes ozonolysis, which is the reaction of ozone with alkenes, alkynes, and azo compounds. Ozonolysis of alkenes forms an ozonide intermediate that can be converted to alcohols, aldehydes, ketones, or carboxylic acids depending on the workup. Alkynes undergo ozonolysis to form diketones or carboxylic acids. Ozonolysis has applications in synthesizing aldehydes, ketones, and drugs, and can be used to determine double bond locations in unknown alkenes.
The document discusses aldol condensation, which is the condensation reaction between two molecules of an aldehyde or ketone to form a β-hydroxy aldehyde or ketone. It occurs when the carbonyl compound has at least one α-hydrogen atom. The reaction involves an aldol reaction followed by a 1,2-elimination and is facilitated by base catalysis. The base typically used is hydroxide ion. Aldol condensation can join different aldehydes and ketones and has applications in synthesis and drug development.
This document discusses the Diels-Alder reaction, which involves a conjugated diene reacting with a dienophile to form a substituted cyclohexene system. It notes that the Diels-Alder reaction is useful for forming 6-membered rings with control over regio- and stereochemistry. The reaction can be reversible under certain conditions. Stereochemical information is retained in the products, with E- and Z-dienophiles giving syn or anti stereochemistry in the adducts. Retrosynthetic analysis can utilize the Diels-Alder reaction.
this ppt include introduction synthesis, physical ,chemical properties, and uses of pyrrole furan and thiophene
also include introduction of 5 membered heterocyclic compound and fused heterocyclic compounds
Sidra Javed prepared this document on phenols. Phenols are aromatic compounds containing one or more OH groups directly attached to the carbon of a benzene ring. The simplest phenol is carbolic acid, C6H5OH. Phenols are more acidic than alcohols due to resonance stabilization of the phenoxide ion. Phenols undergo electrophilic aromatic substitution and oxidation reactions. Common preparation methods for phenols include the base hydrolysis of chlorobenzene, acidic oxidation of cumene, and preparation from aryl diazonium salts.
1. The document discusses various electrophilic addition reactions that can occur with alkenes, including addition of bromine, hydrogen bromide, water, peroxyacids to form epoxides, borane to form alcohols, mercury acetate for oxymercuration-demercuration, and ozone for ozonolysis.
2. Key aspects of the reactions are discussed, including reaction mechanisms and products obtained via Markovnikov or anti-Markovnikov addition.
3. Examples are provided for many of the addition reactions to illustrate how different functional groups are formed depending on the reagents used.
Hydrogenation- definition, catalytic hydrogenation, homogeneous and heterogeneous catalytic hydrogenation, mechanism of catalytic hydrogenation, advantages and disadvantages of catalytic hydrogenation, applications of catalytic hydrogenation
Ozonolysis is the oxidative cleavage of carbon-carbon double bonds using ozone. It involves a three step mechanism: 1) ozone inserts into the double bond to form an unstable primary ozonide, 2) the primary ozonide decomposes to a carbonyl and carbonyl oxide through retro cycloaddition, 3) the carbonyl oxide undergoes cycloaddition again with another carbonyl to form a stable ozonide. The ozonide intermediate can then be worked up using reducing or oxidizing agents to yield different products such as aldehydes, ketones, alcohols, or carboxylic acids.
The document discusses aldol condensation, an organic reaction where two molecules of an aldehyde or ketone undergo a condensation reaction in the presence of a base to yield a β–hydroxyaldehyde or β–hydroxyketone. It involves the reaction of an enolate ion, formed from deprotonation of an aldehyde, with a carbonyl compound to form an aldol. This may then undergo dehydration to form a conjugated enone. The mechanism proceeds through enolate formation, carbon-carbon bond formation between the enolate and carbonyl, and protonation to form the aldol intermediate. Crossed aldol condensation refers to the reaction between two different aldehyde or ketone
The Cannizzaro reaction involves the base-induced disproportionation of two aldehyde molecules to yield a carboxylic acid and a primary alcohol. A hydroxide ion attacks the carbonyl group of an aldehyde, forming an unstable intermediate anion. This intermediate donates a hydride ion to a second aldehyde molecule, converting one to an alcohol and the other to a carboxylic acid. Overall, the reaction disproportionates two aldehydes into an acid and alcohol.
Lithium aluminium hydride (LAH) is a strong reducing agent that is commonly used to reduce carbonyl groups, esters, amides, nitriles, epoxides, lactones, and haloalkanes/haloarenes. LAH is prepared through the reaction of lithium hydride with aluminum chloride. It is a white solid that reacts violently with water, producing hydrogen gas, so reactions must be performed under anhydrous conditions. The mechanism of LAH involves nucleophilic hydride attack on the carbonyl carbon to form an intermediate tetrahedral structure.
1. Diazotization is a reaction where an aryl amine like aniline reacts with nitrous acid to form an unstable diazonium ion intermediate.
2. Coupling reactions involve this diazonium ion reacting with compounds containing activating groups like phenol or aniline to form an azo product by joining the two aryl groups.
3. The coupling reaction is an electrophilic aromatic substitution that proceeds through a two-step mechanism where the diazonium ion attacks the aromatic ring in the first slow step.
E1 &E2 mechanism, sandmeyer and benzyne mechanismlsk1976
The document discusses the Sandmeyer reaction, which is a type of radical-nucleophilic aromatic substitution reaction that replaces an amino group on an aromatic ring with different substituents. During the reaction, the amino group is converted to a diazonium salt that can then be transformed into various functional groups using a catalyst. It also describes the reaction of halobenzenes with potassium amide in liquid ammonia to yield aniline, which proceeds through an elimination-addition mechanism involving the elimination of an alpha hydrogen and addition of an amide anion to form an intermediate benzyne structure.
Electrophilic substitution reactions involve replacing a hydrogen atom in an aromatic ring with an electrophilic group such as nitro, halogen, sulfonic acid or alkyl/acyl groups. This is done using electrophiles generated in situ with a Lewis acid catalyst. It proceeds by generation of an electrophile, formation of a carbocation intermediate through attack on the aromatic ring, and removal of a proton. Ortho/para directing groups activate the ring towards substitution at those positions, while meta directing groups deactivate the ring at ortho/para positions. Polynuclear aromatic hydrocarbons with more than two fused benzene rings can be carcinogenic if inhaled from incomplete combustion.
The Claisen rearrangement is a thermal rearrangement reaction discovered by Rainer Ludwig Claisen in which the allyl group of a phenolic allyl ether migrates ortho to the phenol group. Key characteristics of the Claisen rearrangement are the inversion of the migrating allyl carbon and the intramolecular, unimolecular nature of the reaction. The mechanism involves a cyclic transition state that allows for migration to the ortho position, or para if both ortho positions are blocked.
The document discusses the Diels-Alder reaction, which involves a diene reacting with a dienophile to form a six-membered ring. Key characteristics include versatility, stereoselectivity, and reversibility. The mechanism involves overlap of the HOMO of the diene and LUMO of the dienophile. The stereochemistry of products is governed by the cis principle and endo rule. Variations include retro Diels-Alder reactions and cycloadditions involving allyl cations/anions.
Baeyer Villiger Oxidation of Ketones, Cannizzaro Reaction, MPVADITYA ARYA
The document summarizes several organic chemistry reactions:
1) The Baeyer-Villiger oxidation reaction involves the oxidation of ketones with peroxy acids to form esters through a rearrangement reaction.
2) The Cannizzaro reaction involves the base-induced disproportionation of two aldehyde molecules to form a carboxylic acid and primary alcohol.
3) The Meerwein-Ponndorf-Verley (MPV) reduction uses aluminum isopropoxide catalyst in isopropanol to reduce aldehydes and ketones to the corresponding alcohols through a reversible reaction.
Favorskii rearrangement is one the important reactions in organic chemistry. Let us have some prior understanding of its mechanism and its applications.
The document summarizes the Darzen condensation reaction, which involves the formation of α,β-epoxy esters (glycidic esters) from aldehydes/ketones and α-halo esters under basic conditions. It provides background on the reaction's history and development. The reaction mechanism proceeds through an initial aldol reaction followed by epoxide ring formation. Examples and applications in multi-step syntheses are described. Limitations include the reaction failing for some aldehydes due to self-condensation and difficultly obtaining high, sole product yields needed for kinetic studies.
The benzoin condensation is a reaction between two molecules of benzaldehyde catalyzed by cyanide ions to form benzoin. It was first reported in 1832 by Liebig and Wöhler. It involves a cyanide ion forming a cyanohydrin intermediate with benzaldehyde, followed by a condensation reaction between the cyanohydrin and another benzaldehyde molecule. This forms benzoin along with the removal of cyanide ions. Benzoin condensation is useful for organic synthesis and producing polymers.
This document presents information about the Perkin reaction, which was discovered in the 19th century by English chemist William Henry Perkin. The Perkin reaction is an aldol condensation that converts an aromatic aldehyde and an acid anhydride to an alpha beta unsaturated cinnamic acid. It involves a four step mechanism - abstraction of alpha hydrogen from the acid anhydride, attack of the carbanion on the carbonyl carbon of benzaldehyde, an intramolecular acetyl shift, and loss of the acetate ion to form the unsaturated carboxylic acid product. The Perkin reaction is used to synthesize cinnamic acids, phytoestrogens, stilbenes, and resver
The document summarizes ozonolysis, which is the reaction of ozone with alkenes, alkynes, and azo compounds. Ozonolysis of alkenes forms an ozonide intermediate that can be converted to alcohols, aldehydes, ketones, or carboxylic acids depending on the workup. Alkynes undergo ozonolysis to form diketones or carboxylic acids. Ozonolysis has applications in synthesizing aldehydes, ketones, and drugs, and can be used to determine double bond locations in unknown alkenes.
The document discusses aldol condensation, which is the condensation reaction between two molecules of an aldehyde or ketone to form a β-hydroxy aldehyde or ketone. It occurs when the carbonyl compound has at least one α-hydrogen atom. The reaction involves an aldol reaction followed by a 1,2-elimination and is facilitated by base catalysis. The base typically used is hydroxide ion. Aldol condensation can join different aldehydes and ketones and has applications in synthesis and drug development.
This document discusses the Diels-Alder reaction, which involves a conjugated diene reacting with a dienophile to form a substituted cyclohexene system. It notes that the Diels-Alder reaction is useful for forming 6-membered rings with control over regio- and stereochemistry. The reaction can be reversible under certain conditions. Stereochemical information is retained in the products, with E- and Z-dienophiles giving syn or anti stereochemistry in the adducts. Retrosynthetic analysis can utilize the Diels-Alder reaction.
this ppt include introduction synthesis, physical ,chemical properties, and uses of pyrrole furan and thiophene
also include introduction of 5 membered heterocyclic compound and fused heterocyclic compounds
Sidra Javed prepared this document on phenols. Phenols are aromatic compounds containing one or more OH groups directly attached to the carbon of a benzene ring. The simplest phenol is carbolic acid, C6H5OH. Phenols are more acidic than alcohols due to resonance stabilization of the phenoxide ion. Phenols undergo electrophilic aromatic substitution and oxidation reactions. Common preparation methods for phenols include the base hydrolysis of chlorobenzene, acidic oxidation of cumene, and preparation from aryl diazonium salts.
1. The document discusses various electrophilic addition reactions that can occur with alkenes, including addition of bromine, hydrogen bromide, water, peroxyacids to form epoxides, borane to form alcohols, mercury acetate for oxymercuration-demercuration, and ozone for ozonolysis.
2. Key aspects of the reactions are discussed, including reaction mechanisms and products obtained via Markovnikov or anti-Markovnikov addition.
3. Examples are provided for many of the addition reactions to illustrate how different functional groups are formed depending on the reagents used.
Hydrogenation- definition, catalytic hydrogenation, homogeneous and heterogeneous catalytic hydrogenation, mechanism of catalytic hydrogenation, advantages and disadvantages of catalytic hydrogenation, applications of catalytic hydrogenation
Ozonolysis is the oxidative cleavage of carbon-carbon double bonds using ozone. It involves a three step mechanism: 1) ozone inserts into the double bond to form an unstable primary ozonide, 2) the primary ozonide decomposes to a carbonyl and carbonyl oxide through retro cycloaddition, 3) the carbonyl oxide undergoes cycloaddition again with another carbonyl to form a stable ozonide. The ozonide intermediate can then be worked up using reducing or oxidizing agents to yield different products such as aldehydes, ketones, alcohols, or carboxylic acids.
The document discusses aldol condensation, an organic reaction where two molecules of an aldehyde or ketone undergo a condensation reaction in the presence of a base to yield a β–hydroxyaldehyde or β–hydroxyketone. It involves the reaction of an enolate ion, formed from deprotonation of an aldehyde, with a carbonyl compound to form an aldol. This may then undergo dehydration to form a conjugated enone. The mechanism proceeds through enolate formation, carbon-carbon bond formation between the enolate and carbonyl, and protonation to form the aldol intermediate. Crossed aldol condensation refers to the reaction between two different aldehyde or ketone
The Cannizzaro reaction involves the base-induced disproportionation of two aldehyde molecules to yield a carboxylic acid and a primary alcohol. A hydroxide ion attacks the carbonyl group of an aldehyde, forming an unstable intermediate anion. This intermediate donates a hydride ion to a second aldehyde molecule, converting one to an alcohol and the other to a carboxylic acid. Overall, the reaction disproportionates two aldehydes into an acid and alcohol.
Lithium aluminium hydride (LAH) is a strong reducing agent that is commonly used to reduce carbonyl groups, esters, amides, nitriles, epoxides, lactones, and haloalkanes/haloarenes. LAH is prepared through the reaction of lithium hydride with aluminum chloride. It is a white solid that reacts violently with water, producing hydrogen gas, so reactions must be performed under anhydrous conditions. The mechanism of LAH involves nucleophilic hydride attack on the carbonyl carbon to form an intermediate tetrahedral structure.
1. Diazotization is a reaction where an aryl amine like aniline reacts with nitrous acid to form an unstable diazonium ion intermediate.
2. Coupling reactions involve this diazonium ion reacting with compounds containing activating groups like phenol or aniline to form an azo product by joining the two aryl groups.
3. The coupling reaction is an electrophilic aromatic substitution that proceeds through a two-step mechanism where the diazonium ion attacks the aromatic ring in the first slow step.
E1 &E2 mechanism, sandmeyer and benzyne mechanismlsk1976
The document discusses the Sandmeyer reaction, which is a type of radical-nucleophilic aromatic substitution reaction that replaces an amino group on an aromatic ring with different substituents. During the reaction, the amino group is converted to a diazonium salt that can then be transformed into various functional groups using a catalyst. It also describes the reaction of halobenzenes with potassium amide in liquid ammonia to yield aniline, which proceeds through an elimination-addition mechanism involving the elimination of an alpha hydrogen and addition of an amide anion to form an intermediate benzyne structure.
Electrophilic substitution reactions involve replacing a hydrogen atom in an aromatic ring with an electrophilic group such as nitro, halogen, sulfonic acid or alkyl/acyl groups. This is done using electrophiles generated in situ with a Lewis acid catalyst. It proceeds by generation of an electrophile, formation of a carbocation intermediate through attack on the aromatic ring, and removal of a proton. Ortho/para directing groups activate the ring towards substitution at those positions, while meta directing groups deactivate the ring at ortho/para positions. Polynuclear aromatic hydrocarbons with more than two fused benzene rings can be carcinogenic if inhaled from incomplete combustion.
The Claisen rearrangement is a thermal rearrangement reaction discovered by Rainer Ludwig Claisen in which the allyl group of a phenolic allyl ether migrates ortho to the phenol group. Key characteristics of the Claisen rearrangement are the inversion of the migrating allyl carbon and the intramolecular, unimolecular nature of the reaction. The mechanism involves a cyclic transition state that allows for migration to the ortho position, or para if both ortho positions are blocked.
The document discusses the Diels-Alder reaction, which involves a diene reacting with a dienophile to form a six-membered ring. Key characteristics include versatility, stereoselectivity, and reversibility. The mechanism involves overlap of the HOMO of the diene and LUMO of the dienophile. The stereochemistry of products is governed by the cis principle and endo rule. Variations include retro Diels-Alder reactions and cycloadditions involving allyl cations/anions.
Baeyer Villiger Oxidation of Ketones, Cannizzaro Reaction, MPVADITYA ARYA
The document summarizes several organic chemistry reactions:
1) The Baeyer-Villiger oxidation reaction involves the oxidation of ketones with peroxy acids to form esters through a rearrangement reaction.
2) The Cannizzaro reaction involves the base-induced disproportionation of two aldehyde molecules to form a carboxylic acid and primary alcohol.
3) The Meerwein-Ponndorf-Verley (MPV) reduction uses aluminum isopropoxide catalyst in isopropanol to reduce aldehydes and ketones to the corresponding alcohols through a reversible reaction.
The Dakin reaction involves the oxidation of an ortho- or para-hydroxylated phenyl aldehyde or ketone with hydrogen peroxide in a basic solution. This results in the oxidation of the carbonyl group to a benzenediol and the formation of a carboxylate. The reaction proceeds through a nucleophilic addition, 1,2 aryl migration, hydrolysis, and phenoxide ion formation steps. The reactivity depends on factors like the electrophilicity of the carbonyl carbon and the speed of the 1,2 migration. Phenyl aldehydes react faster than ketones and ortho-hydroxy compounds faster than para-hydroxy derivatives in weak basic conditions. Electron donating groups increase reactivity while electron
1. The document discusses addition reactions of C-C multiple bonds, specifically alkenes and alkynes. It describes various reagents that add across the double or triple bonds, such as hydrogen halides, water, and halogens.
2. Markovnikov's rule is explained, stating that hydrogen adds to the carbon with more hydrogen substituents in alkene additions. Anti-Markovnikov additions are also possible using peroxides.
3. Methods to form alcohols from alkenes like acid-catalyzed hydration and oxymercuration-demercuration are described.
1. The document discusses addition reactions of C-C multiple bonds, specifically alkenes and alkynes. It describes various reagents that add across the double or triple bonds, such as hydrogen halides, water, and halogens.
2. Markovnikov's rule is explained, stating that hydrogen adds to the carbon with more hydrogen substituents in alkene additions. Anti-Markovnikov additions are also possible using peroxides.
3. Methods to form alcohols from alkenes like acid-catalyzed hydration and oxymercuration-demercuration are described.
The document discusses the crossed aldol condensation reaction. It describes the 5 step mechanism where the hydroxide ion deprotonates an aldehyde to form an enolate ion, which then adds to the carbonyl carbon of a non-enolizable aldehyde. This forms an aldol product that can further react. The carbonyl group plays a role in providing a site for nucleophilic attack and making the alpha hydrogens acidic. Crossed aldol condensation allows control over donor and acceptor molecules. It is useful for synthesizing large molecules from small starting materials and occurs in biological synthesis of fructose from glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.
This document discusses the Cannizzaro reaction, which involves the disproportionation of aldehydes in the presence of a strong base to form an alcohol and a carboxylic acid. It provides the history and mechanism of the reaction, including the requirements of aromatic or aliphatic aldehydes without alpha hydrogens and an aqueous alkaline catalyst. Examples of the reaction and limitations are also covered, along with crossed and intramolecular variants.
This document is a chemistry project on aldehydes, ketones, and carboxylic acids. It includes a certificate verifying completion, acknowledgements, index, and 5 sections discussing topics like nomenclature, preparation methods, reactions, and inductive effects. The project was assigned by a teacher and completed by a 12th grade student to fulfill an academic requirement. It provides an overview of key concepts regarding these functional groups in an educational format.
The benzoin addition is an addition reaction involving two aldehydes. The reaction generally occurs between aromatic aldehydes or glyoxals. The reaction produces an acyloin. In the classic application benzaldehyde is converted to benzoin
The document summarizes various reactions of aldehydes and ketones. It describes how aldehydes and ketones undergo nucleophilic addition reactions, with the nucleophile attacking the carbonyl carbon. This forms an alkoxide intermediate which gives an alcohol upon protonation. It also discusses the relative reactivities of aldehydes and ketones, hydrate and cyanohydrin formation, imine formation, oxidation and reductions of carbonyl compounds, acetal formation, and the Wittig reaction.
This document summarizes catalytic hydrogenation, including:
- Heterogenous catalytic hydrogenation occurs on metal surfaces like Ni, Pd, Pt.
- Homogenous hydrogenation uses complexes like Wilkinson's catalyst in solution.
- Rate of reduction decreases with increased substitution. Selective reduction of double bonds is possible.
- Catalytic hydrogenation is stereospecific, giving syn-addition and racemic mixtures for cis-alkenes.
This document discusses various aldol condensation reactions and their mechanisms. It introduces crossed aldol condensation which produces up to four products from two different carbonyl compounds. Self-aldol condensation uses a single aldehyde or ketone. Intramolecular aldol condensation occurs when a molecule contains two carbonyl groups. Several industrial reactions are also summarized, including the Aldox process, Perkin reaction, and Meerwein-Ponndorf-Verley reaction. In conclusion, these reactions are reversible and complete conversion can be achieved through excess alcohol or acetone removal.
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
This document provides information on the topic of homogeneous catalysis. It discusses several types of homogeneous catalysis including hydrogenation, hydroformylation, hydrocyanation, and Wilkinson catalysts. Hydrogenation involves adding hydrogen to organic compounds using molecular hydrogen and a catalyst. Hydroformylation adds a formyl group and hydrogen to an alkene. Hydrocyanation converts alkenes to nitriles. Wilkinson's catalyst is [RhCl(PPh3)3] and is widely used for hydrogenation reactions.
The document discusses several examples of homogeneous catalysis including hydrogenation, hydroformylation, hydrocyanation, and Wilkinson's catalyst. It provides details on the mechanisms and applications of these reactions. Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants, usually liquid phase. The catalysts are molecularly dispersed and mass transfer limitations are less of an issue.
The aldol condensation reaction allows carbonyl compounds with an α-hydrogen atom to undergo condensation. It is a reversible reaction that proceeds through an enolate intermediate formed when hydroxide deprotonates the α-hydrogen. The enolate then acts as a nucleophile that attacks the electrophilic carbonyl carbon of an aldehyde or ketone. Protonation of the resulting alkoxide forms the β-hydroxy aldehyde or ketone product. The reaction can join two different aldehydes or ketones in a crossed-aldol condensation that expands the synthetic possibilities.
The aldol condensation reaction allows carbonyl compounds containing an α-hydrogen atom to undergo condensation. It is a reversible reaction that proceeds through an enolate intermediate formed when hydroxide deprotonates the α-hydrogen. The enolate then acts as a nucleophile that attacks the electrophilic carbonyl carbon of an aldehyde or ketone. Protonation of the resulting alkoxide forms the β-hydroxy aldehyde or ketone product. The reaction can join two different aldehydes or ketones in a crossed-aldol condensation that expands the synthetic possibilities.
The combination of a carbonyl group and a hydroxyl on the same carbon atom is called a carboxyl group. Compounds containing the carboxyl group are called carboxylic acids. The carboxyl group is one of the most widely occurring functional groups in organic chemistry.
Aromatic Carboxylic acids: Carboxylic acids have an aryl group bound to the carboxyl group is known as aromatic carboxylic acids. The general formula of an aliphatic aromatic carboxylic acid is Ar-COOH.
Acidity of carboxylic acid:
A carboxylic acid may dissociate in water to give a proton and a carboxylate ion. Dissociation of a carboxylic acid involves breaking an O-H bond gives a carboxylate ion with the negative charge spread out equally over two oxygen atoms, compared with just one oxygen atom in an alkoxide ion. The delocalized charge makes the carboxylate ion more stable therefore; dissociation of a carboxylic acid to a carboxylate ion is less endothermic.
Preparation Methods:
1. Oxidation:
The oxidation of aldehyde with oxidizing agents such as CrO3 to forms carboxylic acids containing the same numbers of carbon atoms with a oxidizing agents like chromic acid, chromium trioxide. The silver oxide (Ag2O) in aqueous ammonia solution (Tollen’s reagent) is mild reagent give good yield at room temperature. E.g. Acetaldehyde reacts with CrO3 in aqueous acid to give acetic acid.
2. Grignard reagents (from CO2):
Carboxylic acid can be prepared by the reaction of Grignard reagent (alkyl magnesium halide) with carbon dioxide (CO2) in presence of dry ether. Grignard reagents react with carbon dioxide to forms a magnesium carboxylates which on hydrolysis by dilute HCl produces carboxylic acids.
3. Hydrolysis of nitrile:
The hydrolysis of nitrile or cyanide in presence of dilute acid to forms a carboxylic acid. In this reaction –CN group is converted to a –COOH group.
4. Hydrolysis Reactions:
All the carboxylic acid derivatives can be hydrolyzed into the carboxylic acid in the acidic or basic media; the hydrolysis reaction is fast and occurs in presence of water with no acid or base catalyst.
1. From Ester (Hydrolysis of ester): Ester can be hydrolyzed in either acidic or basic medium to yield carboxylic acid. The ester is heated with an excess of water contains strong acid or base catalyst.
Properties of Carboxylic Acids:
1. Low molecular weights carboxylic acids are colourless liquid at room temperature i.e. lower member ate liquid up to C9 and have characteristic odors whereas higher members are solid.
2. Carboxylic acids are polar organic compound. Low molecular weight carboxylic acids (first four members) are soluble in water whereas solubility in water decrease as molecular weight and chain lengthing increases.
3. Aromatic acids are insoluble in water.
4. Carboxylic acids have higher melting and boiling point due to their capacity to readily form stable hydrogen-bonded dimers.
In 1891,Emil fischer devised a method of representing the 3D structures of
molecules in 2D Structures on a plane (Paper) by convention, horizontal line
represent bonds projecting from the plane of paper towards the observer and
vertical line represent away from the observer
Flash photolysis and Shock tube method PRUTHVIRAJ K
In 1967 the Nobel prize in chemistry was awarded to Manfred Eigen, Ronald George Wreyford Norrish for their co-discovery of Flash photolysis in 1949.
Flash photolysis is used to extensively to study reactions that happen extremely quickly, even down to the femtosecond depending on the laser that is used. The technique was born out of cameras developed during and shorty after WWII, which were used to take pictures of fast moving planes, rockets and Missiles.
Since then the technology of laser and optics has progressed allowing faster and faster reactions to be studied.
A silicate is an anions consisting of silicon and oxygen.
Silicates occur in earth’s crust in abundantly in the form of silicate minerals and aluminosilicate clay.
Silicate anions are often large polymeric molecules with an extense variety of structures,including chains and rings.double chains and sheets.
Silicates are extremely important materials, both natural and artificial, for all sorts of technological and artistic activities.
FUNCTIONAL GROUP MODIFICATION : Medicinal ChemistryPRUTHVIRAJ K
Once a lead compound or a pharmacophore structure with the desired pharmacological effect has been identified, organic chemists can introduce modifications in the chemical structure of the lead compound with the goal of improving the pharmacokinetics or pharmacodynamics of a drug candidate. These evolved structures are known as analogs.
3
IDENTIFICATION OF ACTIVE PART : THE PHARMACOPHOREPRUTHVIRAJ K
Portion of the molecule containing the essential organic functional groups that directly interact with the receptor active site and are responsible for the activity are know as pharmacophore.
Pharmacophore model represents the binding mode of active molecules to their target.
A pharmacophore model differentiates between active and inactive molecule.
STRUCTURE MODIFICATION TO INCREASE POTENCY AND THERAPEUTIC INDEX PRUTHVIRAJ K
1. It is a tool of research in medicinal chemistry to refine molecule.
2.Most of the molecules are modified either by altering its physical properties or by modifying chemical structure.
Structure modification is chemical alteration of known and previously characterized.
lead compound for the purpose of enhancing its usefulness as a drug (to improve activity).
This could mean enhancing its specificity for a particular body target site, increasing its potency.
Examples:
Progesterone and estradiol among the sex hormones
Nucleophilic Substitution reaction (SN1 reaction)PRUTHVIRAJ K
Attack of nucleophile at a saturated carbon atom bearing substituent, known as leaving group results in Substitution reaction.
The group that is displaced (leaving group) carries its bonding electrons.
The new bond is formed between nucleophile and the carbon using the electrons supplied by the nucleophilic agent.
The compound on which substitution takes place is called “substrate.”
The substrate consists of two parts, alkyl group and leaving group.
UNIMOLECULAR SURFACE REACTION: MECHANISM, INHIBITION AND ACTIVATION ENERGYPRUTHVIRAJ K
Unimolecular surface reaction may involve a reaction between a molecule A of the reactant and vacant site S on the surface
Surface reaction involving single adsorbed molecules and therefore term as unimolecular and are treated by Langmuir adsorption isotherm
Kinetics of Pyrolysis of acetaldehyde PRUTHVIRAJ K
Jeevankumar M presented a seminar on the pyrolysis of acetaldehyde under the guidance of Mr. Pruthviraj. Pyrolysis is the thermal degradation of compounds in the absence of oxygen above the boiling point of water. The pyrolysis of acetaldehyde occurs through a chain reaction, producing methyl radicals and hydrogen. The mechanism involves initiation, propagation, and termination steps. Applying steady-state approximations, the rate law for the pyrolysis of acetaldehyde was determined to be third order with respect to acetaldehyde concentration. Pyrolysis has applications in producing fuels from waste and in industrial processes like steelmaking and syngas production.
Diel's-Alder and Gattermann Koch ReactionsPRUTHVIRAJ K
n organic chemistry, the Diels–Alder reaction is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene derivative. It is the prototypical example of a pericyclic reaction with a concerted mechanism
The Chichibabin reaction is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. The following is the overall form of the general reaction: The direct amination of pyridine with sodium amide takes place in liquid ammonia
Pigments and Colors: Natural Pigments or Plant Pigments PRUTHVIRAJ K
Biological pigments, also known simply as pigments or biochromes, are substances produced by living organisms that have a color resulting from selective color absorption. Biological pigments include plant pigments and flower pigment
The document discusses different types of food colourants. It describes natural food colourants that are synthesized naturally, nature-identical colourants that are synthesized to mimic natural ones, and artificial/synthetic colourants. Seven synthetic colours are approved by the FDA for food use. Natural colours come from vegetable, animal, mineral or other sources. Carotenoids provide yellow, orange and red colours and have health benefits. Beta-carotene is an important carotenoid used as a food colourant. Betalains and chlorophylls are also used as natural food colourants. Anthoxanthins contribute cream and white colours while lycopene provides the red colour of tomatoes.
The document discusses chirality in heteroatom systems where chirality arises from a non-carbon centre. It explains that compounds containing nitrogen, phosphorus, sulfur or other atoms can exhibit stereochemistry when the atom forms a tetrahedral structure with four different groups. The stereochemistry of these compounds provides useful information for drug applications. It then focuses on the specific stereochemistry of various nitrogen, phosphorus and sulfur compounds, including amines, oximes, azo compounds, phosphines and sulfoxides. It describes how these compounds can exhibit geometrical isomers, inversion barriers, and retention or inversion of configuration under chemical reactions.
Conformational analysis of medium ringsPRUTHVIRAJ K
The document discusses the conformations of medium-sized carbocyclic rings from cycloheptane to cyclodecane. Cycloheptane exists in two sets of conformers, with the preferred conformers being twist-chair. Medium rings from cyclooctane to cyclodecane exhibit unusual features like intraannular and extraannular hydrogens leading to transannular strain. Cyclodecane preferentially adopts a boat-chair-boat conformation to minimize these interactions. Pseudorotation in these rings can be slowed by introducing substituents that restrict bond rotation.
Pigments and Colors:Extraction and PurificationPRUTHVIRAJ K
Pigments and Colors:Extraction and Purification- Extraction of naturally occurring pigments like anthocyanins, tannins etc from their sources and purification methods
The document discusses helicity and chirality in organic chemistry. It explains that helicity arises in molecules with a helical shape, which are inherently chiral. It also describes how overcrowding in molecules like helicenes can lead to helicity. The document then discusses asymmetric synthesis and how existing chiral centers induce asymmetric induction to form diastereomers in unequal amounts. It presents Cram's rule and Prelog's rule as methods to predict the configuration of the predominant diastereomer based on the existing chiral centers.
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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1. NAMED REACTIONS IN ORGANIC
SYNTHESIS: CANNIZZARO REACTION
By
PRUTHVIRAJ K
2. CANNIZZARO REACTION
When reacted with concentrated NaOH (50 wt%) or other strong bases (e.g., alkoxides),
aliphatic and aromatic aldehydes with no α-hydrogen undergo an intermolecular
hydride-transfer reaction known as the Cannizzaro reaction. In this disproportionation
reaction, one molecule of aldehyde oxidizes another to the corresponding carboxylic acid
and is reduced to the corresponding primary alcohol in a maximum 50% yield.
If the aldehyde has α-hydrogens, the aldol reaction will take place faster than the
Cannizzaro reaction. Alternatively, high yields of alcohol can be obtained from almost any
aldehyde when the reaction is performed in the presence of an excess of formaldehyde.
This process is called the crossed Cannizzaro reaction.
α-Keto aldehydes undergo an intramolecular Cannizzaro reaction. This method, however,
has been rendered obsolete by the emergence of hydride reducing agents in 1946. In the
presence of an appropriate Lewis acid catalyst, the intramolecular Cannizzaro reaction
takes place with stereocontrol, yielding synthetically useful α-hydroxy esters directly from
readily available glyoxals under neutral conditions.It has also been shown that the reaction
rates are enhanced significantly when the Cannizzaro reaction is performed under
solvent-free conditions.
PRUTHVIRAJ K, MSc, CHEM MASTER
3. Mechanism
A variety of mechanisms have been proposed for this reaction, but the generally accepted
mechanism of the
Cannizzaro reaction involves a hydride transfer. First, OH- adds across the carbonyl group, and the
resulting species is deprotonated under the applied basic conditions to give the corresponding
dianion. This dianion facilitates the ability of the aldehydic hydrogen to leave as a hydride ion. This
leaving hydride ion attacks another aldehyde molecule in the rate-determining step (RDS) to afford
the alkoxide of a primary alcohol, which gets protonated by the solvent (H2O).
By running the reaction in the presence of D2O, it was shown that the reducing hydride ion came
from another aldehyde and not the reaction medium, since the resulting primary alcohol did not
contain a deuterium. Ashby and co-workers using resolved ESR spectra demonstrated that
substituted benzaldehyde radical anions were
formed in the reactions of substituted benzaldehydes with either NaOH or KOt-Bu. This
observation suggested that the reaction proceeded by a single-electron transfer (SET) mechanism.
PRUTHVIRAJ K, MSc, CHEM MASTER
5. Synthetic applications.
• J. Rebek et al. synthesized novel dibenzoheptalene bislactones via a double intramolecular Cannizzaro reaction
for condensation polymerization and remote catalysis studies. These bislactones are chiral, atropisomeric
molecules
During the large-scale, high-yield, one-pot synthesis of 4-chloro-3-(hydroxymethyl)pyridine, a starting material for the
preparation of several polyfunctionalized molecules that can be linked to cephalosporines, M. Penso and co-workers utilized
the combination of direct regioselective lithiation/formylation and crossed-Cannizzaro reduction of 4-chloropyridine
PRUTHVIRAJ K, MSc, CHEM MASTER