This document is a lecture on carbon-carbon bond formation reactions in organic chemistry. It covers various main group and transition metal reagents that can be used to form C-C bonds, including organolithium, organomagnesium, organozinc, organocopper, organochromium, organocobalt and organopalladium reagents. Specific reactions discussed include alkylation of enolates, aldol reactions, conjugate additions, Grignard additions, Reformatsky reactions, Heck reactions and more. Examples are provided to illustrate reaction mechanisms and strategies for controlling stereochemistry.
This document summarizes the aromatic nucleophilic substitution (SNAr) reaction mechanism. It involves the formation of a carbanion intermediate called the Meisenheimer intermediate through an addition-elimination process. Aryl halides are relatively unreactive toward nucleophilic substitution, but reactivity increases in the presence of electron-withdrawing groups due to stabilization of the carbanion. Under highly forcing conditions, aryl halides can undergo substitution through a benzyne intermediate that has been trapped using Diels-Alder reactions.
The Suzuki reaction is a palladium-catalyzed cross-coupling reaction between boronic acids or esters with organic halides, triflates, or other boron-containing compounds. This reaction occurs under basic conditions and leads to the formation of carbon-carbon single bonds, typically between an aryl or vinyl group and another aryl or vinyl group. It is commonly used to synthesize biaryl compounds. The reaction proceeds through oxidative addition, transmetallation, and reductive elimination steps. Key advantages are mild reaction conditions and availability of boronic acids. The Suzuki reaction has applications in synthesizing pharmaceuticals, agrochemicals, and natural products.
The document introduces the Heck reaction, which is a coupling reaction where a metal catalyst aids in coupling two hydrocarbon fragments. Specifically, the Heck reaction involves converting a terminal alkene to an internal alkene. Richard Heck, Ei-ichi Negishi, and Akira Suzuki were jointly awarded the Nobel Prize in 2010 for their work developing palladium-catalyzed C-C cross coupling reactions, including the Heck reaction. The mechanism of the Heck reaction involves oxidative addition, insertion, β-H elimination, and reductive elimination steps.
The document discusses the Wagner-Meerwein rearrangement, a reaction first observed in 1899 where a carbocation is generated followed by a [1,2]-shift of an adjacent carbon-carbon bond to form a new carbocation. This reaction was not fully understood until 1922 when its ionic nature was revealed. The rearrangement involves the migration of hydrogen, alkyl, or aryl groups between carbocations and can involve multiple consecutive shifts. It can be initiated through various means to generate the initial carbocation and the migrating group retains its stereochemistry.
This document is a seminar submission on catalytic hydrogenation by S.F. Pimple for their M. Pharm program. It contains an introduction, definitions, types of reduction reactions, and details on catalytic hydrogenation including the mechanism, advantages, limitations, applications, and references. The objective is to study catalytic hydrogenation in detail and understand its mechanism. It discusses heterogeneous and homogeneous catalytic hydrogenation and common catalysts used like palladium, Adams catalyst, and Raney nickel. The mechanism involves hydrogen bonding to the metal catalyst, weakening of the alkene pi bond, and transfer of hydrogen atoms to form the saturated alkane product.
The document discusses the Von Richter rearrangement and Smiles rearrangement.
The Von Richter rearrangement involves the displacement of a nitro group by cyanide ion on an aromatic compound, with the carboxyl group entering ortho to the displaced nitro group. Evidence supports a mechanism where one oxygen of the carboxyl group comes from the nitro group and one from solvent.
The Smiles rearrangement involves an intramolecular nucleophilic substitution where a leaving group is displaced by a nucleophile activated by an ortho nitro group. Examples are given of substrates that undergo Smiles rearrangement where the linking chain can be aromatic or aliphatic. Electron withdrawing groups para to the nucleophile retard the
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.
This document summarizes the aromatic nucleophilic substitution (SNAr) reaction mechanism. It involves the formation of a carbanion intermediate called the Meisenheimer intermediate through an addition-elimination process. Aryl halides are relatively unreactive toward nucleophilic substitution, but reactivity increases in the presence of electron-withdrawing groups due to stabilization of the carbanion. Under highly forcing conditions, aryl halides can undergo substitution through a benzyne intermediate that has been trapped using Diels-Alder reactions.
The Suzuki reaction is a palladium-catalyzed cross-coupling reaction between boronic acids or esters with organic halides, triflates, or other boron-containing compounds. This reaction occurs under basic conditions and leads to the formation of carbon-carbon single bonds, typically between an aryl or vinyl group and another aryl or vinyl group. It is commonly used to synthesize biaryl compounds. The reaction proceeds through oxidative addition, transmetallation, and reductive elimination steps. Key advantages are mild reaction conditions and availability of boronic acids. The Suzuki reaction has applications in synthesizing pharmaceuticals, agrochemicals, and natural products.
The document introduces the Heck reaction, which is a coupling reaction where a metal catalyst aids in coupling two hydrocarbon fragments. Specifically, the Heck reaction involves converting a terminal alkene to an internal alkene. Richard Heck, Ei-ichi Negishi, and Akira Suzuki were jointly awarded the Nobel Prize in 2010 for their work developing palladium-catalyzed C-C cross coupling reactions, including the Heck reaction. The mechanism of the Heck reaction involves oxidative addition, insertion, β-H elimination, and reductive elimination steps.
The document discusses the Wagner-Meerwein rearrangement, a reaction first observed in 1899 where a carbocation is generated followed by a [1,2]-shift of an adjacent carbon-carbon bond to form a new carbocation. This reaction was not fully understood until 1922 when its ionic nature was revealed. The rearrangement involves the migration of hydrogen, alkyl, or aryl groups between carbocations and can involve multiple consecutive shifts. It can be initiated through various means to generate the initial carbocation and the migrating group retains its stereochemistry.
This document is a seminar submission on catalytic hydrogenation by S.F. Pimple for their M. Pharm program. It contains an introduction, definitions, types of reduction reactions, and details on catalytic hydrogenation including the mechanism, advantages, limitations, applications, and references. The objective is to study catalytic hydrogenation in detail and understand its mechanism. It discusses heterogeneous and homogeneous catalytic hydrogenation and common catalysts used like palladium, Adams catalyst, and Raney nickel. The mechanism involves hydrogen bonding to the metal catalyst, weakening of the alkene pi bond, and transfer of hydrogen atoms to form the saturated alkane product.
The document discusses the Von Richter rearrangement and Smiles rearrangement.
The Von Richter rearrangement involves the displacement of a nitro group by cyanide ion on an aromatic compound, with the carboxyl group entering ortho to the displaced nitro group. Evidence supports a mechanism where one oxygen of the carboxyl group comes from the nitro group and one from solvent.
The Smiles rearrangement involves an intramolecular nucleophilic substitution where a leaving group is displaced by a nucleophile activated by an ortho nitro group. Examples are given of substrates that undergo Smiles rearrangement where the linking chain can be aromatic or aliphatic. Electron withdrawing groups para to the nucleophile retard the
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.
Nitrenes slideshare Reactive intermediatesDivyarani K
The document discusses nitrenes, which are electron deficient nitrogen species that can exist in singlet or triplet states. It describes various methods for generating nitrenes, such as through the decomposition of azides or oxidation of primary amino groups. The document also outlines several reactions of nitrenes, including their ability to insert into carbon-hydrogen bonds or undergo rearrangement reactions like the Hofmann, Curtius, Lossen, and Schmidt rearrangements.
This document discusses ligand substitution reactions in octahedral complexes. It describes the main mechanisms of ligand substitution including dissociative (SN1), associative (SN2), and concerted (interchange) pathways. It also discusses hydrolysis reactions and anation reactions as types of ligand substitutions. Specific examples are provided of acid and base hydrolysis in octahedral cobalt complexes, and factors that influence the reaction mechanisms and rates are outlined.
Organolithium compounds and their preparation.pptxZaeem36
Here, the detailed explanation of organolithium compounds in this presentation you will find out about:
organolithium introduction
-Preparation
-Properties
-And their useful Reactions,
for more projects and any kind of presentations you can contact us at:
zaeem.bzn@gmail.com
The Lindemann-Hinshelwood mechanism explains how first-order unimolecular gas-phase reactions can occur through collisions. It proposes that: (1) A reactant molecule A becomes energized through a collision with another A molecule, forming the excited species A*. (2) A* then either loses its excess energy through another collision or undergoes unimolecular decay to form products P. (3) If the unimolecular decay is the slowest step, the overall reaction appears first-order. The mechanism predicts a transition to second-order kinetics at low pressures when bimolecular collisions become rate-determining.
1) Pericyclic reactions proceed in a concerted, one-step process via a cyclic transition state with high stereo selectivity. They include cycloadditions, electrocyclic reactions, and sigmatropic rearrangements.
2) Cycloadditions are classified as (2+2) or (4+2) depending on the number of pi electrons involved. Diels-Alder reactions are a common example of a (4+2) cycloaddition.
3) Electrocyclic reactions involve the formation or breaking of a ring with the generation or loss of a pi bond. They can be analyzed using frontier molecular orbital theory and orbital symmetry correlation diagrams.
SMILES REARRANGEMENT [REACTION AND MECHANISM]Shikha Popali
The Smiles rearrangement is an intramolecular aromatic nucleophilic substitution reaction. It involves the migration of a substituent X from one carbon of an aromatic ring to another, with an aromatic substituent Y acting as the nucleophile. A specific example provided is the migration of an SO2Ar group to the ortho position of an ArO- nucleophile, activated by an adjacent nitro group. The X group is usually S, SO, or SO2, while the Y nucleophile is typically the conjugate base of OH, NH2, NHR or SH, though even CH2 has been used.
Annulenes and Heteroannulenes - Premie FernandesBebeto G
This document discusses annulenes and heteroannulenes. Annulenes are monocyclic conjugated systems represented by the general formula (CH)2m and include benzene and cyclooctatetraene. Heteroannulenes contain one or more heteroatoms in the ring, such as pyridine and thiophene. Aromaticity in these systems is determined by Huckel's rule of (4n+2)π electrons. The document examines various annulene and heteroannulene structures of different ring sizes and whether they obey Huckel's rule and exhibit aromatic, anti-aromatic, or non-aromatic behavior.
1. The von Richter reaction involves reacting aromatic nitro compounds with potassium cyanide, which results in the displacement of the nitro group and addition of a carboxyl group in the ortho position through cine substitution.
2. The reaction mechanism eluded chemists for almost 100 years before the currently accepted one was proposed.
3. This reaction is an example of cine aromatic nucleophilic substitution where the nitro group is replaced by a carboxylic group, which is always in the ortho position. However, the reaction has limited application and poor yields.
Addition reactions occur when two reactants combine to form a new product with no leftover atoms. In an addition reaction, new groups are added to the starting material, breaking a pi bond and forming two sigma bonds. Addition reactions involve the addition of electrophiles, radicals, or nucleophiles across multiple bonds such as carbon-carbon double or triple bonds.
DIBAL-H is a commercially available selective reducing agent that can reduce esters and nitriles to the corresponding aldehydes. It is prepared by heating triisobutylaluminum, which induces beta hydride elimination to form DIBAL-H and isobutene. DIBAL-H selectively reduces esters to aldehydes at low temperatures through a tetrahedral intermediate. Hydrolytic workup of this intermediate then yields the desired aldehyde products. The document provides an introduction to DIBAL-H including its preparation, applications in organic synthesis, and how it differs from other reducing agents like LiAlH4.
The document summarizes the Tiffeneau–Demjanov rearrangement reaction. It was discovered in the early 1900s by French chemist Marc Émile Pierre Adolphe Tiffeneau and Russian chemist Nikolay Yakovlevich Demyanov. The reaction involves treating 1-aminomethyl-cycloalkanol with nitrous acid to form an enlarged cycloketone through a 1,2-carbon migration. This ring expansion reaction is useful for increasing the size of amino-substituted cyclic compounds from four to eight-membered rings. The mechanism involves diazotization of the amine to form a diazonium ion that undergoes 1,2-alkyl shift accompanied by nitrogen loss to form
Pyridinium chlorochromate (PCC) is a mild oxidizing agent used to selectively oxidize primary alcohols to aldehydes and secondary alcohols to ketones. It has the formula [C5H5NH]+ [CrO3Cl]- and is a stable, commercially available reagent that is soluble in organic solvents and provides high yields in oxidation reactions. While effective, it can form viscous byproducts that complicate product isolation and the reagent itself is toxic.
This document provides an overview of reduction reactions in organic chemistry. It discusses various types of reduction reactions including catalytic hydrogenation, hydride transfer reactions using reagents like LiAlH4 and NaBH4, dissolving metal reductions, and others. Specific metal hydride reductions using boron and aluminum reagents like sodium borohydride, sodium cyanoborohydride, lithium aluminum hydride, and diisobutylaluminum hydride are explained in detail including their mechanisms and selectivity. Diimide reduction is also briefly covered. The document concludes with a bibliography of reference books on organic reaction mechanisms.
This document summarizes a student's report on carbocation reaction intermediates. It introduces carbocations as positively charged carbon species that are generally unstable. The document then covers:
- Classification of primary, secondary, and tertiary carbocations
- Carbocation structure and generation mechanisms
- Factors that influence carbocation stability such as inductive effects, hyperconjugation, and resonance
- Common reactions of carbocations including combination with nucleophiles, elimination of protons, addition to unsaturated systems, and intramolecular rearrangements.
what is metal allyl complex
what is the definition of metal allyl complex
what are synthesis of metal allyl complex
what are reaction of metal allyl complex
summary of metal allyl complex
Retrosynthes analysis and disconnection approach ProttayDutta1
Retrosynthetic analysis is a technique used to plan organic syntheses by working backwards from the target molecule. It involves mentally deconstructing the target molecule through sequential disconnections and functional group transformations until commercially available starting materials are reached. Each disconnection produces synthons, which are idealized fragments that represent possible reaction precursors. Common types of disconnections include C-X, C-C, and carbonyl bonds. The goal of retrosynthesis is to simplify the target structure and design multiple possible synthesis routes leading from simple starting materials to the target. It helps chemists discover efficient syntheses by considering the reactivity, selectivity, and availability of materials at each step.
This document summarizes aromatic nucleophilic substitution reactions. It discusses the SNAr, SN1, and benzyne mechanisms. For SNAr, a strong withdrawing group is needed for reactivity. SN1 is rare for aromatics. In the benzyne mechanism, elimination of H forms benzyne which then adds the nucleophile, producing either ortho or para substituted products. Radiocarbon labeling is used to identify the products. In summary, the document outlines different aromatic nucleophilic substitution reaction mechanisms and factors affecting their reactivity.
This document provides an overview of organometallic chemistry. It discusses various organometallic reagents including Grignard reagents, organolithium reagents, organocuprate reagents, and their reactions. It also summarizes important organometallic reactions such as the Suzuki coupling and ring closing metathesis. Organometallic chemistry allows the formation of carbon-carbon bonds that were previously difficult to form using classical organic synthesis.
Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants. Common homogeneous catalysts include acids and bases in aqueous solutions. Homogeneous catalysts can provide selectivity in terms of chemoselectivity, regioselectivity, diastereoselectivity, and enantioselectivity. Important reaction types for homogeneous catalysis include oxidative addition, reductive elimination, migratory insertion, and β-hydride elimination. Key reactions discussed are hydrogenation, hydroformylation, hydrocyanation, and applications of Ziegler-Natta catalysts and Wilkinson's catalyst. Chiral induction with chiral ligands is also discussed for producing chiral molecules in drug synthesis such as L-DOPA
Nitrenes slideshare Reactive intermediatesDivyarani K
The document discusses nitrenes, which are electron deficient nitrogen species that can exist in singlet or triplet states. It describes various methods for generating nitrenes, such as through the decomposition of azides or oxidation of primary amino groups. The document also outlines several reactions of nitrenes, including their ability to insert into carbon-hydrogen bonds or undergo rearrangement reactions like the Hofmann, Curtius, Lossen, and Schmidt rearrangements.
This document discusses ligand substitution reactions in octahedral complexes. It describes the main mechanisms of ligand substitution including dissociative (SN1), associative (SN2), and concerted (interchange) pathways. It also discusses hydrolysis reactions and anation reactions as types of ligand substitutions. Specific examples are provided of acid and base hydrolysis in octahedral cobalt complexes, and factors that influence the reaction mechanisms and rates are outlined.
Organolithium compounds and their preparation.pptxZaeem36
Here, the detailed explanation of organolithium compounds in this presentation you will find out about:
organolithium introduction
-Preparation
-Properties
-And their useful Reactions,
for more projects and any kind of presentations you can contact us at:
zaeem.bzn@gmail.com
The Lindemann-Hinshelwood mechanism explains how first-order unimolecular gas-phase reactions can occur through collisions. It proposes that: (1) A reactant molecule A becomes energized through a collision with another A molecule, forming the excited species A*. (2) A* then either loses its excess energy through another collision or undergoes unimolecular decay to form products P. (3) If the unimolecular decay is the slowest step, the overall reaction appears first-order. The mechanism predicts a transition to second-order kinetics at low pressures when bimolecular collisions become rate-determining.
1) Pericyclic reactions proceed in a concerted, one-step process via a cyclic transition state with high stereo selectivity. They include cycloadditions, electrocyclic reactions, and sigmatropic rearrangements.
2) Cycloadditions are classified as (2+2) or (4+2) depending on the number of pi electrons involved. Diels-Alder reactions are a common example of a (4+2) cycloaddition.
3) Electrocyclic reactions involve the formation or breaking of a ring with the generation or loss of a pi bond. They can be analyzed using frontier molecular orbital theory and orbital symmetry correlation diagrams.
SMILES REARRANGEMENT [REACTION AND MECHANISM]Shikha Popali
The Smiles rearrangement is an intramolecular aromatic nucleophilic substitution reaction. It involves the migration of a substituent X from one carbon of an aromatic ring to another, with an aromatic substituent Y acting as the nucleophile. A specific example provided is the migration of an SO2Ar group to the ortho position of an ArO- nucleophile, activated by an adjacent nitro group. The X group is usually S, SO, or SO2, while the Y nucleophile is typically the conjugate base of OH, NH2, NHR or SH, though even CH2 has been used.
Annulenes and Heteroannulenes - Premie FernandesBebeto G
This document discusses annulenes and heteroannulenes. Annulenes are monocyclic conjugated systems represented by the general formula (CH)2m and include benzene and cyclooctatetraene. Heteroannulenes contain one or more heteroatoms in the ring, such as pyridine and thiophene. Aromaticity in these systems is determined by Huckel's rule of (4n+2)π electrons. The document examines various annulene and heteroannulene structures of different ring sizes and whether they obey Huckel's rule and exhibit aromatic, anti-aromatic, or non-aromatic behavior.
1. The von Richter reaction involves reacting aromatic nitro compounds with potassium cyanide, which results in the displacement of the nitro group and addition of a carboxyl group in the ortho position through cine substitution.
2. The reaction mechanism eluded chemists for almost 100 years before the currently accepted one was proposed.
3. This reaction is an example of cine aromatic nucleophilic substitution where the nitro group is replaced by a carboxylic group, which is always in the ortho position. However, the reaction has limited application and poor yields.
Addition reactions occur when two reactants combine to form a new product with no leftover atoms. In an addition reaction, new groups are added to the starting material, breaking a pi bond and forming two sigma bonds. Addition reactions involve the addition of electrophiles, radicals, or nucleophiles across multiple bonds such as carbon-carbon double or triple bonds.
DIBAL-H is a commercially available selective reducing agent that can reduce esters and nitriles to the corresponding aldehydes. It is prepared by heating triisobutylaluminum, which induces beta hydride elimination to form DIBAL-H and isobutene. DIBAL-H selectively reduces esters to aldehydes at low temperatures through a tetrahedral intermediate. Hydrolytic workup of this intermediate then yields the desired aldehyde products. The document provides an introduction to DIBAL-H including its preparation, applications in organic synthesis, and how it differs from other reducing agents like LiAlH4.
The document summarizes the Tiffeneau–Demjanov rearrangement reaction. It was discovered in the early 1900s by French chemist Marc Émile Pierre Adolphe Tiffeneau and Russian chemist Nikolay Yakovlevich Demyanov. The reaction involves treating 1-aminomethyl-cycloalkanol with nitrous acid to form an enlarged cycloketone through a 1,2-carbon migration. This ring expansion reaction is useful for increasing the size of amino-substituted cyclic compounds from four to eight-membered rings. The mechanism involves diazotization of the amine to form a diazonium ion that undergoes 1,2-alkyl shift accompanied by nitrogen loss to form
Pyridinium chlorochromate (PCC) is a mild oxidizing agent used to selectively oxidize primary alcohols to aldehydes and secondary alcohols to ketones. It has the formula [C5H5NH]+ [CrO3Cl]- and is a stable, commercially available reagent that is soluble in organic solvents and provides high yields in oxidation reactions. While effective, it can form viscous byproducts that complicate product isolation and the reagent itself is toxic.
This document provides an overview of reduction reactions in organic chemistry. It discusses various types of reduction reactions including catalytic hydrogenation, hydride transfer reactions using reagents like LiAlH4 and NaBH4, dissolving metal reductions, and others. Specific metal hydride reductions using boron and aluminum reagents like sodium borohydride, sodium cyanoborohydride, lithium aluminum hydride, and diisobutylaluminum hydride are explained in detail including their mechanisms and selectivity. Diimide reduction is also briefly covered. The document concludes with a bibliography of reference books on organic reaction mechanisms.
This document summarizes a student's report on carbocation reaction intermediates. It introduces carbocations as positively charged carbon species that are generally unstable. The document then covers:
- Classification of primary, secondary, and tertiary carbocations
- Carbocation structure and generation mechanisms
- Factors that influence carbocation stability such as inductive effects, hyperconjugation, and resonance
- Common reactions of carbocations including combination with nucleophiles, elimination of protons, addition to unsaturated systems, and intramolecular rearrangements.
what is metal allyl complex
what is the definition of metal allyl complex
what are synthesis of metal allyl complex
what are reaction of metal allyl complex
summary of metal allyl complex
Retrosynthes analysis and disconnection approach ProttayDutta1
Retrosynthetic analysis is a technique used to plan organic syntheses by working backwards from the target molecule. It involves mentally deconstructing the target molecule through sequential disconnections and functional group transformations until commercially available starting materials are reached. Each disconnection produces synthons, which are idealized fragments that represent possible reaction precursors. Common types of disconnections include C-X, C-C, and carbonyl bonds. The goal of retrosynthesis is to simplify the target structure and design multiple possible synthesis routes leading from simple starting materials to the target. It helps chemists discover efficient syntheses by considering the reactivity, selectivity, and availability of materials at each step.
This document summarizes aromatic nucleophilic substitution reactions. It discusses the SNAr, SN1, and benzyne mechanisms. For SNAr, a strong withdrawing group is needed for reactivity. SN1 is rare for aromatics. In the benzyne mechanism, elimination of H forms benzyne which then adds the nucleophile, producing either ortho or para substituted products. Radiocarbon labeling is used to identify the products. In summary, the document outlines different aromatic nucleophilic substitution reaction mechanisms and factors affecting their reactivity.
This document provides an overview of organometallic chemistry. It discusses various organometallic reagents including Grignard reagents, organolithium reagents, organocuprate reagents, and their reactions. It also summarizes important organometallic reactions such as the Suzuki coupling and ring closing metathesis. Organometallic chemistry allows the formation of carbon-carbon bonds that were previously difficult to form using classical organic synthesis.
Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants. Common homogeneous catalysts include acids and bases in aqueous solutions. Homogeneous catalysts can provide selectivity in terms of chemoselectivity, regioselectivity, diastereoselectivity, and enantioselectivity. Important reaction types for homogeneous catalysis include oxidative addition, reductive elimination, migratory insertion, and β-hydride elimination. Key reactions discussed are hydrogenation, hydroformylation, hydrocyanation, and applications of Ziegler-Natta catalysts and Wilkinson's catalyst. Chiral induction with chiral ligands is also discussed for producing chiral molecules in drug synthesis such as L-DOPA
This document provides an overview of alcohols including their structure, nomenclature, physical properties, synthesis, and reactions. Alcohols contain an -OH group bonded to a carbon. They can be synthesized through hydration of alkenes, reduction of aldehydes/ketones/acids/esters, or Grignard reactions. Alcohols undergo reactions to form salts, alkyl halides, esters, aldehydes, ketones, and carboxylic acids. Their properties and reactivity depend on whether the -OH group is bonded to a primary, secondary, or tertiary carbon.
This document summarizes a seminar presentation on organocopper reagents. It introduces organometallic compounds and discusses the preparation of Gilman reagents by reacting an organolithium compound with copper(I) halide. It describes the structure of Gilman reagents and their reactivity in nucleophilic substitution, conjugate addition, and syn addition reactions to alkynes. The document compares the reactivity of organocopper reagents to organomagnesium reagents and gives an example of the Corey-House synthesis using organocopper reagents.
This document provides an overview of alkyl halides for a medical biochemistry course. It defines alkyl halides as halogen-substituted alkanes and discusses their physical properties. Two common methods for preparing alkyl halides from alcohols are described: reaction with sulfur halides like thionyl chloride or phosphorus halides like phosphorus tribromide. The document also summarizes nucleophilic substitution reactions of alkyl halides and the SN1 and SN2 reaction mechanisms.
Embrace digital chemistry data with expert insights
How will chemistry data change in the coming years? Do research practices need to morph alongside it?
In the second webinar in the series, join Professor Simon Coles (University of Southampton), Lynn Kamerlin (Georgia Tech), May Copsey and Anna Rulka (Royal Society of Chemistry) as they explore what the future holds for chemistry data.
TRANSITION METAL CATALYSIS , THE DIFFERENT METALS OF TRANSITION USED AS CATALYTIC REAGENT WITH ITS PROPERTIES , THEIR CHARGE TRANSFER ITS REACTION INCLUDING COPPER, PALLADIUM FOLLWED BY HECKMAN, ULLMAN COUPLING REACTION, GILLMAN REACTION, HECK REACTION
- Organometallic compounds contain a carbon-metal bond and are important organic reagents, such as Grignard reagents (RMgX).
- Organometallic compounds provide a source of nucleophilic carbon that can react with electrophilic carbons to form new carbon-carbon bonds, allowing synthesis of complex molecules from simple starting materials.
- Common reactions involve organolithium (RLi) and Grignard (RMgX) reagents adding to the carbonyl groups in aldehydes, ketones, and esters to form alcohols.
This document provides an overview of 9 organic reactions: 1) Metal hydride reduction using NaBH4 and LiAlH4, 2) Clemmensen reduction, 3) Birch reduction, 4) Wolff-Kishner reaction, 5) Oppenauer oxidation, 6) Dakin reaction, 7) Beckmann rearrangement, 8) Schmidt rearrangement, and 9) Claisen-Schmidt condensation. For each reaction, it discusses the reaction mechanism, modifications, and applications in organic synthesis and drug development. The document serves as a reference for graduate students and researchers on important carbonyl reactions and their uses in pharmaceutical chemistry.
B.phram
Semester .4
Subject : Organic chemistry - III
Use as reference and also usable for examination prearation.
gtu afflitited phramacy college's student may using this ppt.
This document discusses reduction reactions and reducing agents. It aims to teach the reader to: 1) exploit differences in reactivity between hydride and neutral reducing agents to achieve chemoselective reductions; 2) use substrate chirality to control syn vs. anti diastereoselectivity in ketone reductions; 3) rationalize reaction outcomes using transition state diagrams; 4) appreciate the versatility of transition metals in reductions; 5) understand the utility of dissolving metal reductions; and 6) use radical chemistry for deoxygenation and halide reduction. It then provides details on various hydride and neutral reducing agents, focusing on their reactivities and applications in selective reductions.
HSSC Second year Chemistry course slides for Federal Board Pakistan, lectures by Dr. Raja Hashim Ali (also available on Youtube as a series of video lectures).
Gilman reagent, also known as organocopper reagents, are prepared by reacting organomagnesium, organolithium, or organozinc reagents with copper(I) salts. Gilman reagents react with a variety of electrophiles including acid chlorides, aldehydes, ketones, epoxides, and alkyl halides. Some common reactions of Gilman reagents are: 1) reactions with acid chlorides to form ketones, 2) coupling reactions between two different alkyl halides to form C-C bonds, and 3) conjugate addition reactions of the organocopper reagent to unsaturated carbonyl compounds like enones. Gilman reagents offer advantages over Grignard reagents for
Ppt on Organometallic Compounds-Zamir ShekhZAMIR SHEKH
The document discusses various types of organometallic compounds, including their definitions, nomenclature, properties, structures, and reactions. It describes organolithium, organomagnesium, organozinc, organocopper, and other organometallic compounds. It also discusses their applications in synthesis such as additions, displacements, conjugate additions, cyclopropanation, and opening of epoxides.
B.Sc.TY.organic syntesis involving enpolates kohinoor College Khultabad.pptNamdeoWaltureGuru
The document summarizes key aspects of alkylation reactions of carbon nucleophiles. It discusses methods for generating carbon nucleophiles like enolates and enamines, factors that determine their regioselectivity and reactivity, and their alkylation reactions. Some key points include:
1) Enolates can be generated by deprotonation of carbon acids using strong bases like organolithium reagents under kinetic or thermodynamic control. Polar aprotic solvents favor kinetic enolates while protic solvents allow equilibration.
2) The regioselectivity of enolate formation is influenced by substituents, counterions, and solvents. Kinetic enolates favor less substituted car
This document summarizes key reactions involving carbonyl compounds, including addition, condensation, and substitution reactions. It discusses the mechanisms of addition reactions involving carbonyl compounds and factors that influence the reactivity. Specific reactions covered include hydration, acetal formation, nucleophilic addition, ester hydrolysis, aminolysis, acylation, aldol condensation, Claisen condensation, Dieckmann condensation, Michael addition, Robinson annulation, and carbonyl substitution reactions.
The document discusses the classification, nomenclature, preparation, properties and reactions of alcohols. Alcohols can be classified based on the number of hydroxyl groups and the carbon they are attached to. The IUPAC system names alcohols based on the parent chain and hydroxyl position. Alcohols can be prepared from alkyl halides, alkenes, carbonyl compounds and by reduction. They have higher boiling points than other organic compounds due to hydrogen bonding. Primary alcohols undergo SN2 reactions while tertiary undergo SN1. Oxidation of primary alcohols yields aldehydes and secondary yields ketones.
This chapter discusses carbon-carbon bond formation through reactions between nucleophilic carbon intermediates and electrophilic carbons. It focuses on the alkylation of enolates, enamines, and imine anions generated from ketones, aldehydes, esters, amides, and nitriles. Key topics include the factors that determine the stability and reactivity of various carbon nucleophiles, such as substituents and reaction conditions. Solvent effects and the regioselectivity, stereoselectivity, and site selectivity of alkylation reactions are also examined. Specific examples illustrate principles such as kinetic vs. thermodynamic control and the use of chiral auxiliaries to achieve enantioselectivity.
The document discusses disposal, recycling, and applications of post-consumer PET polymer. It is authored by Dr. V. Sivamurugan of Pachaiyappa's College in Chennai, India. The document covers disposal methods, chemical recycling through glycolysis, and applications of recycled PET polymer.
This document provides an overview of acids and bases according to different theories:
1) Arrhenius concept defines acids and bases as compounds that release H+ and OH- ions in water.
2) Bronsted-Lowry concept defines acids as proton donors and bases as proton acceptors in any reaction.
3) Lewis concept defines acids as electron pair acceptors and bases as electron pair donors, forming coordinate covalent bonds.
Buffer solutions maintain pH upon addition of small amounts of acid or base and are important in biological systems like blood plasma.
Synthesis of Pyrimidines and purines.
Structure and role of nucleic acids. DNA and RNA Genetic code.
Biosynthesis of cholesterol, phenanthrene alkaloids and bile acids.
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This document contains a lecture presentation by Dr. V. Sivamurugan on the synthesis of target molecules and ring systems. It discusses various strategies for ring formation through intramolecular reactions and cyclization reactions. Specific reactions covered include Diels-Alder reactions, Robinson annulations, and Baldwin's rules for ring closure. Examples of retrosynthesis and synthesis of compounds containing 5-membered and 6-membered rings are provided.
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How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
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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.
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Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
Pollock and Snow "DEIA in the Scholarly Landscape, Session One: Setting Expec...
Lecture 1 c c bond formation
1. D R . V. S I VAM U R U G A N
P R O F E S S O R I N C H E M I S T RY
PAC H A I YA P PA’ S C O L L E G E , C H E N N AI –
6 0 0 0 3 0
S I VAAT N U S @ G M A I L . C O M
FORMATION C-C BOND
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1
4. 1.1 Main-group chemistry
1.1.1 Alkylation of enolates and enamines
1.1.2 Conjugate addition reactions of enolates and enamines
1.1.3 The aldol reaction
1.1.4 Asymmetric methodology with enolates and enamines
1.1.5 Organolithium reagents
1.1.6 Organomagnesium reagents
1.1.7 Organozinc reagents
1.1.8 Allylic organometallics of boron, silicon and tin
1.2 Transition-metal chemistry
1.2.1 Organocopper reagents
1.2.2 Organochromium chemistry
1.2.3 Organocobalt chemistry
1.2.4 Organopalladium chemistry
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5. 1.1.1 ALKYLATION OF ENOLATES AND
ENAMINES
Carbonyl groups increase the acidity of the proton(s)
adjacent (α-) to the carbonyl group.
The acidity of the C-H bonds in these compounds is
caused by a combination of the inductive electron-
withdrawing effect of the unsaturated groups and the
resonance stabilization of the anion formed by removal
of a proton
Order of electron withdrawing capacity:
NO2>COR>SO2R>CO2R>CN>C6H5
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7. • It is these enolate anions that are involved in many reactions
of carbonyl compounds, such as the aldol condensation, and
in bimolecular nucleophilic displacements
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8. TABLE 1.1. APPROXIMATE ACIDITIES OF SOME ACTIVATED
COMPOUNDS AND COMMON REAGENTS
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9. • In the presence of a protic acid, ketones may be
converted largely into the enol form, implicated in many
acid-catalysed reactions of carbonyl compounds.
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10. ALKYLATION ON ENOLATE
• Alkylation of enolate anions is achieved readily with alkyl halides or
other alkylating agents.
• Both primary and secondary alkyl, allyl or benzyl halides may be
used successfully
• tertiary halides poor yields of alkylated product often result because
of competing elimination.
• Advantageous - proceed by way of the toluene-p-sulfonate,
methanesulfonate or trifluoromethanesulfonate rather than a halide.
• The sulfonates are excellent alkylating agents and can usually be
obtained from the alcohol in a pure condition more readily than
corresponding halides
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11. With secondary and tertiary allylic halides or sulfonates, reaction of an enolate
anion may give mixtures of products formed by competing attack at the α- andγ-
positions
Dialkylation also becomes a more serious problem with the more acidic
cyanoacetic esters and in alkylations with very reactive electrophiles such as allyl
or benzyl halides or sulfonates
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18. 1.1.2 CONJUGATE ADDITION REACTIONS
OF ENOLATES AND ENAMINES
Addition to α,β-unsaturated carbonyl or nitrile compounds to the enolates –
Micheal addition
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19. ADDITION OF PHENYL VINYL
SULFOXIDE
• The electron-withdrawing group is commonly an ester or ketone, but can
be an amide, nitrile, nitro, sulfone, sulfoxide, phosphonate or other
suitable group capable of stabilizing the intermediate anion.
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34. STEREOSELECTIVE ALDOL REACTIONS
• the syn or the anti (traditionally erythro and threo) aldol product can be
prepared. This is often termed a diastereoselective reaction
• suitable chiral auxiliaries or catalysts, high selectivities for one enantiomer of
the syn or the anti diastereomer can be obtained -enantioselective reactions
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36. ZIMMERMAN–TRAXLER MODEL
chair-like six membered cyclic transition state in which the ligated metal atom is
bonded to the oxygen atoms of the aldehyde and the enolate
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45. 1.1.6 ORGANOMAGNESIUM REAGENTS
• Organomagnesium reagents are commonly referred to
as Grignard reagents.
• Typically, a Grignard reagent is formed by reaction of an
alkyl halide (RX) in ethereal solvent with magnesium to
give the species RMgX.
• The ethereal solvent co-ordinates to the magnesium
atom and the Grignard reagents are in equilibrium with
the dialkylmagnesium species R2Mg and MgX2 (Schlenk
equilibrium).
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47. ASYMMETRIC GRIGNARD REAGENTS
• Asymmetric induction occurs in the addition of a Grignard reagent to an
aldehyde or ketone bearing a chiral auxiliary.
• An example is the use of the 8-phenylmenthol ester 138, in which Grignard
addition to the aldehyde occurs from the front face opposite the bulky
substituent on the auxiliary and with the conformation of the carbonyl groups
cis to one another
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50. 1.1.7 ORGANOZINC REAGENTS
Organozinc compounds are less nucleophilic and less basic
than the corresponding organolithium or organomagnesium
reagents.
They can therefore effect chemoselective carbon–carbon
bond formation in the presence of otherwise reactive
functional groups.
The most common method for the formation of an organozinc
reagent involves the insertion of zinc metal into the carbon–
iodine bond of an alkyl iodide.
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52. CYCLISATION TO LACTONE
Insertion of zinc into allyl bromides occurs readily, for example to give the allyl
zinc reagent 145.
Addition to an aldehyde occurs by attack through the γ-carbon atom to give a
homoallylic alcohol.
With substrate 145, bearing a β–ester group, the product homoallylic alcohol
cyclizes spontaneously to give the lactone 146.
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53. In the presence of a Lewis acid, alkyl zinc halides react with aromatic aldehydes
to give secondary alcohols.
However, alkyl zinc reagents are less reactive than their allyl derivatives and
reaction with aliphatic aldehydes is very sluggish.29-12-2018 53
56. 1.1.8 ALLYLIC ORGANOMETALLICS OF
BORON, SILICON AND TIN
A useful reaction in organic synthesis is the addition of an allylic
organometallic reagent to a carbonyl group.
A number of different metals can be employed, although those of
boron, silicon and tin have found the most use.
The carbon–carbon bond-forming step is often stereoselective and
generates the versatile homoallylic alcohol unit
Oxidative cleavage of the product alkene to the aldehyde (or other
carbonyl derivative) provides the -hydroxy-carbonyl compound and
offers an alternative stereoselective approach to the aldol-type
product.
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61. 1.2 TRANSITION-METAL CHEMISTRY
The use of transition metals to promote the formation of
carbon–carbon bonds has grown tremendously in recent
years.
This section describes some of the important
transformations using the metals copper, chromium,
cobalt and palladium.
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62. 1.2.1 ORGANOCOPPER REAGENTS
• There are various types of stoichiometric organocopper
reagent, the most common being R2CuLi, RCu(CN)Li or
R2Cu(CN)Li2.
• For example, a lithium dialkylcuprate species, R2CuLi, often
referred to as a Gilman reagent, is most conveniently
prepared by reaction of two equivalents of an organolithium
compound with copper(I) iodide in diethyl ether
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67. THE E-ALKENE IS FORMED FROM THE E-ALKENYL HALIDE.
LIKEWISE, THE Z-ALKENE IS FORMED SELECTIVELY FROM THE
Z-ALKENYL HALIDE.
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68. 1.2.2 ORGANOCHROMIUM CHEMISTRY
• Arylchromium complexes can be prepared easily, simply
by heating the arene with chromium hexacarbonyl,
Cr(CO)6 or by ligand exchange with
(naphthalene)chromium tricarbonyl complex.
• The desired arylchromium complex is generated, bearing
the arene (η6 species) and three carbon monoxide
ligands on the chromium(0) atom (18 electron complex)
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73. 1.2.3 ORGANOCOBALT CHEMISTRY
• The most common use of cobalt in organic synthesis is
as its alkyne complex.
• Addition of dicobalt octacarbonyl [Co2(CO)8] to an alkyne
generates the stable organocobalt complex 184 that
exists as a tetrahedral cluster
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74. PAUSON–KHAND REACTION
• The reaction combines the alkyne, alkene and carbon
monoxide, in what is formally a [2+2+1] cyclo addition
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76. 1.2.4 ORGANOPALLADIUM CHEMISTRY
Organopalladium species tolerate many different functional groups
and promote a variety of carbon–carbon (and other) bond-forming
reactions with extremely high chemo- and regioselectivity.
Oxidative addition of palladium(0) species into unsaturated halides
or triflates provides a popular method for the formation of the -bound
organopalladium(II)species.
Organopalladium species generated by oxidative addition react with
organometallic species or with compounds containing a π-bond,
such as alkynes or alkenes.
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77. It is important to use an unsaturated (e.g. aryl or alkenyl) halide or
triflate, as β-hydride elimination of alkyl palladium species can take
place readily.
Oxidative addition of palladium(0) into alkenyl halides (or triflates)
occurs stereospecifically with retention of configuration.
The palladium is typically derived from
tetrakis(triphenylphosphine)palladium(0), [Pd(PPh3)4], or
tris(dibenzylideneacetone) dipalladium(0), [Pd2(dba)3], or by in situ
reduction of a palladium(II) species such as [Pd(OAc)2] or
[Pd(PPh3)2Cl2].
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