Polar Reactions. Indian Institute of Technology Madras CH 3 OH 2 -H 2 O CH 2. HCl. H 3 C CH 3 neopentyl alcohol CH 3 CH 3. 1,2-shift -H + H 3 C
|
|
- Margaret Hood
- 5 years ago
- Views:
Transcription
1 Polar Reactions Important points to be discussed in this module: 1. Chemistry of Carbocations with respect to: a. 1,2-shifts of carbocations b. Pinacol-pinacolone rearrangement c. Semipinacolone rearrangement 2. Chemistry of Carbanions: a. Alkylation and acylation of enolates b. Aldol condensation c. Michael reaction d. Claisen and Dieckman condensation reactions Chemistry of Carbocations During the Friedel-Crafts alkylation, we saw that n-propyl cation ( C 2 C 2 ) undergoes rearrangement to give rise to a more stable secondary carbocation (C 3 C 2 ). The driving force for this reaction is generation of a more stable carbocation it is estimated that approximately 16 kcal/mol (67 kj/mol) is gained by conversion of a primary to a secondary or a secondary to tertiary carbocation. These types of rearrangements are broadly classified as Wagner-erwein rearrangements and involve 1,2-shift of an adjacent group. These types of reactions are common to all the reactions which involve carbocation intermediate and the fate of the carbocation intermediate is dependent of the reaction conditions. The reaction of neopentylic alcohol with a mineral acid such as Cl can nicely illustrate this point. In this reaction, depending on the exact reaction conditions, varying amounts 2-methyl-2-butene and 2- chloro-2-methylbutane are formed and neopentyl chloride is conspicuous by its absence! neopentyl alcohol Cl 2-2 C 2 1,2-shift 2-methyl-2-butene - CCl - 3C 3 Cl 2-chloro-2-methylbutane 1
2 What happens in this transformation then? The answer to this question could be obtained by writing the mechanism for this transformation. In the first step, the Cl protonates the hydroxyl group of the neopentyl alcohol which leads to dehydration and subsequent formation of neopentylic carboaction. This intermediate is extremely short lived and rearranges via the migration of a methyl group along with its pair of bonding electrons to generate a more stable tertiary carbocation. This process of intramolecular migration is considerably faster than the intermolecular trapping of the carbocation with solvent or chloride nucleophile. The migration of a group from one carbon to an adjacent carbocation is commonly encountered when the reactive intermediate involved is carbocations and is commonly referred to as 1,2-shift. Pinacol Rearrangement: 1,2-diols, known as pinacols, also undergo a similar type of dehydration reaction when treated with acid to furnish a ketone or aldehyde which have rearranged structure compared to the initial diol. This transformation is commonly referred to as Pinacol Rearrangement. Let s take an example when pinacol reacts with an acid, it leads to the formation of pincolone. It is believed that this reaction also involves the formation of a tertiary carbocation in the first step which is followed by 1,2-shift of the methyl group. Now, the question will be if we already have a stable carbocation, why should it undergo rearrangement? The answer is - the oxygen lone pair - which can stabilize the newly formed carbocation by donating its lone pair to carbocation, thereby completing octet for all the atoms involved. In fact, one could view this reaction as a push-pull reaction! The carbocation pulls the alkyl group along with its bonding electrons towards itself while the oxygen lone pair pushes the alkyl group away. pinacol pinacolone 2
3 It is clear now that there are two important steps involved in pinacol rearrangement: (1) loss of water from the protonated diol to form the carbocation; and (2) rearrangement of the carbocation by a 1,2-shift to give rise to the protonated ketone. The next question that arises is what happens when the pinacol is unsymmetrical? In such situations, the product obtained is determined (a) by which group is lost in step (1) and then (b) by which group migrates in step (2) to the electron deficient carbon thus formed. The group is usually lost from the carbon atom that will form the more stable carbocation. The rate of migration of the groups in the second step is referred to as the migratory aptitude of the group. Since the rearrangement involves movement of the migrating group with its bonding electrons to an electron deficient centre, migratory aptitudes are greatest for groups in which the migrating atom is most electron rich. It should be kept in mind though that the direction of the rearrangement is largely determined by the relative ease of removal of a group (first step) and rearrangement may not necessarily involve the group of highest migratory aptitude. Et Et C A general order of migratory aptitudes for the pinacol rearrangements is: p-anisyl > p-tolyl > phenyl > tert.-alkyl > primary alkyl > It should be noted however, that even though the migratory aptitudes generally follow the order given above, the absolute comparison depends on the actual reaction and condition. Semipinacol rearrangement: The pinacol type of rearrangement is not limited only to vicinal diols. Deamination of a- amino alcohols also leads to a reaction which closely resembles the pinacol 3
4 rearrangement and is often called the semipinacol rearrangement. In this reaction, nitrous acid is used to form an alkanediazonium ion which readily looses nitrogen to give the intermediate carbocation. N 2 N 2 N 2 -N 2 - This reaction can be used for expansion as well as the contraction of medium sized rings. N 2 N 2 C + N 2 N 2 N 2 + N 2 4
5 Assignment A. Suggest a suitable mechanism for the following reactions. Write each step and show the rearrangement clearly by means of arrow. 1. Cl Cl C Br Br 5
6 B. Identify the products of the following reactions and suggest a mechanism for the 1. reaction N 2 C 2 N 2 N 2 6. N 2 N 2 N 2 6
PAPER No. 5:Organic Chemistry-2(Reaction Mechanism-1) MODULE No. 6: Generation, Structure, Stability and Reactivity of Carbocations
Subject Chemistry Paper No and Title Module No and Title Module Tag Paper No. 5: Organic Chemistry-II (Reaction Mechanism-1) Generation, Structure, Stability and Reactivity of Carbocations CHE_P5_M6 TABLE
More informationREARRANGEMENTS NOTES Mechanistic Aspects of Rearrangements
- 1 - REARRANGEMENTS NOTES Mechanistic Aspects of Rearrangements Nature of the Rearrangement It can vary from being truly stepwise to migration occurring in concert with initial ionisation. These two situations
More informationCHAPTER 19: CARBONYL COMPOUNDS III
CHAPTER 19: CARBONYL COMPOUNDS III A hydrogen bonded to a carbon adjacent to a carbonyl carbon is sufficiently acidic to be removed by a strong base. The carbon adjacent to a carbonyl carbon is called
More informationREACTIONS OF ALCOHOLS Created by: Mohammad Heidarian
Nucleophilic Substitution, β- Elimination, and Oxidation reactions are the main type of reactions associated with alcohols. Nucleophilic Substitution: A reaction in which a nucleophile replaces a leaving
More informationMolecular Rearrangements
Ø Migration of one the molecule group from one atom to another within Ø Generally the migrating group never leaves the molecule Ø There are five types of skeletal rearrangements- 1. Electron deficient
More informationChapter 17. Reactions of Aromatic Compounds
Chapter 17 Reactions of Aromatic Compounds Electrophilic Aromatic Substitution Although benzene s pi electrons are in a stable aromatic system, they are available to attack a strong electrophile to give
More informationChapter 19. Carbonyl Compounds III Reaction at the α-carbon
Chapter 19. Carbonyl Compounds III Reaction at the α-carbon There is a basic hydrogen (α hydrogen) on α carbon, which can be removed by a strong base. 19.1 The Acidity of α-hydrogens A hydrogen bonded
More informationChemistry 2000 Lecture 18: Reactions of organic compounds
hemistry 2000 Lecture 18: Reactions of organic compounds Marc R. Roussel March 6, 2018 Marc R. Roussel Reactions of organic compounds March 6, 2018 1 / 27 Reactions of organic compounds Organic chemists
More informationCHEM Lecture 7
CEM 494 Special Topics in Chemistry Illinois at Chicago CEM 494 - Lecture 7 Prof. Duncan Wardrop ctober 22, 2012 CEM 494 Special Topics in Chemistry Illinois at Chicago Preparation of Alkenes Elimination
More informationChap 11. Carbonyl Alpha-Substitution Reactions and Condensation Reactions
Chap 11. Carbonyl Alpha-Substitution eactions and Condensation eactions Four fundamental reactions of carbonyl compounds 1) Nucleophilic addition (aldehydes and ketones) ) Nucleophilic acyl substitution
More informationChapter 15 Reactions of Aromatic Compounds
Chapter 15 1 Chapter 15 Reactions of Aromatic Compounds Electrophilic Aromatic Substitution Arene (Ar-H) is the generic term for an aromatic hydrocarbon The aryl group (Ar) is derived by removal of a hydrogen
More information12/27/2010. Chapter 15 Reactions of Aromatic Compounds
Chapter 15 Reactions of Aromatic Compounds Electrophilic Aromatic Substitution Arene (Ar-H) is the generic term for an aromatic hydrocarbon The aryl group (Ar) is derived by removal of a hydrogen atom
More informationChapter 16 Aldehydes and Ketones I Nucleophilic Addition to the Carbonyl Group
Chapter 16 Aldehydes and Ketones I Nucleophilic Addition to the Carbonyl Group Nomenclature of Aldehydes and Ketones Aldehydes are named by replacing the -e of the corresponding parent alkane with -al
More informationChapter 16. Aldehydes and Ketones I. Nucleophilic Addition to the Carbonyl Group. Physical Properties of Aldehydes and Ketones. Synthesis of Aldehydes
Nomenclature of Aldehydes and Ketones Chapter 16 Aldehydes and Ketones I. Aldehydes replace the -e of the parent alkane with -al The functional group needs no number Nucleophilic Addition to the Carbonyl
More informationDouble and Triple Bonds. The addition of an electrophile and a
Chapter 11 Additions to Carbon-Carbon Double and Triple Bonds The addition of an electrophile and a nucleophile to a C-C C double or triple bonds 11.1 The General Mechanism Pi electrons of the double bond
More information2.222 Practice Problems 2003
2.222 Practice Problems 2003 Set #1 1. Provide the missing starting compound(s), reagent/solvent, or product to correctly complete each of the following. Most people in the class have not done this type
More informationChapter 16 Aldehydes and Ketones I. Nucleophilic Addition to the Carbonyl Group
Chapter 16 Aldehydes and Ketones I. Nucleophilic Addition to the Carbonyl Group Nomenclature of Aldehydes and Ketones Aldehydes are named by replacing the -e of the corresponding parent alkane with -al
More informationNew bond. ph 4.0. Fischer esterification. New bond 2 O * New bond. New bond H 2N. New C-C bond. New C-C bond. New C-C bond. O Cl.
Iverson C 0N KRE Table: For use in synthesis problems, count carbons in products and starting materials then identify location(s) of new s, especially C-C or C=C s. With that information, use the following
More informationTreatment of cyclooctatetrene with potassium gives you a dianion. Classify the starting material and product as aromatic, antiaromatic or
Treatment of cyclooctatetrene with potassium gives you a dianion. Classify the starting material and product as aromatic, antiaromatic or nonaromatic? 1 2 Classify cyclononatetrene and it s various ions
More informationReactions of Aromatic Compounds. Aromatic compounds do not react like other alkenes. With an appropriate catalyst, however, benzene will react
Reactions of Aromatic Compounds Aromatic compounds do not react like other alkenes 2 Fe 3 2 Does not form A major part of the problem for this reaction is the product has lost all aromatic stabilization,
More informationBSc. II 3 rd Semester. Submitted By Dr. Sangita Nohria Associate Professor PGGCG-11 Chandigarh 1
BSc. II 3 rd Semester Submitted By Dr. Sangita Nohria Associate Professor PGGCG-11 Chandigarh 1 Introduction to Alkyl Halides Alkyl halides are organic molecules containing a halogen atom bonded to an
More informationChapter 15. Reactions of Aromatic Compounds. Electrophilic Aromatic Substitution on Arenes. The first step is the slow, rate-determining step
Electrophilic Aromatic Substitution on Arenes Chapter 15 Reactions of Aromatic Compounds The characteristic reaction of aromatic rings is substitution initiated by an electrophile halogenation nitration
More informationAldol Reactions pka of a-h ~ 20
Enolate Anions Chapter 17 Hydrogen on a carbons a to a carbonyl is unusually acidic The resulting anion is stabilized by resonance to the carbonyl Aldehydes and Ketones II Aldol Reactions pka of a-h ~
More informationPage 1 of 9. Sessional Examination (November 2017) Max Marks: 20 Date: Time: One Hour. Model Answers
Page 1 of 9 Sessional Examination (November 2017) Class: B. Pharm-II yr (III sem) Subject: Pharma Org. Chem-II Max Marks: 20 Date: 14.11.2017 Time: One Hour Model Answers Q. 1. Solve the following (ANY
More informationCHE1502. Tutorial letter 203/1/2016. General Chemistry 1B. Semester 1. Department of Chemistry
E1502/203/1/2016 Tutorial letter 203/1/2016 General hemistry 1B E1502 Semester 1 Department of hemistry This tutorial letter contains the answers to the questions in assignment 3. FIRST SEMESTER: KEY T
More informationElectrophilic Aromatic Substitution. Dr. Mishu Singh Department of chemistry Maharana Pratap Govt.P.G.College Hardoi
Electrophilic Aromatic Substitution Dr. Mishu Singh Department of chemistry Maharana Pratap Govt.P.G.College Hardoi 1 Recall the electophilic addition of HBr (or Br2) to alkenes H + nu cleophile H Br H
More informationAlcohols: Contain a hydroxy group( OH) bonded to an sp 2 or sp 3 hybridized
Lecture Notes hem 51B S. King hapter 9 Alcohols, Ethers, and Epoxides I. Introduction Alcohols, ether, and epoxides are 3 functional groups that contain σ-bonds. Alcohols: ontain a hydroxy group( ) bonded
More informationand Stereochemistry) PAPER 1: ORGANIC CHEMISTRY- I (Nature of Bonding and Stereochemistry) MODULE 4: Applications of Electronic Effects
Subject Chemistry Paper No and Title Module No and Title Module Tag Paper 1: ORGANIC - I (Nature of Bonding Module 4: Applications of Electronic Effects CHE_P1_M4 PAPER 1: ORGANIC - I (Nature of Bonding
More informationBackground Information
ackground nformation ntroduction to Condensation eactions Condensation reactions occur between the α-carbon of one carbonyl-containing functional group and the carbonyl carbon of a second carbonyl-containing
More informationOrganic Chemistry Lecture 2 - Hydrocarbons, Alcohols, Substitutions
ALKANES Water-insoluble, low density C-C single bonds Higher MW -> higher BP, higher MP Branching -> lower BP, higher MP Forms cycloalkanes which can have ring strain Cyclohexane: chair vs. boat configuration
More informationLecture Topics: I. Electrophilic Aromatic Substitution (EAS)
Reactions of Aromatic Compounds Reading: Wade chapter 17, sections 17-1- 17-15 Study Problems: 17-44, 17-46, 17-47, 17-48, 17-51, 17-52, 17-53, 17-59, 17-61 Key Concepts and Skills: Predict and propose
More informationStudy of Chemical Reactions
Study of Chemical Reactions Introduction to Mechanisms There are four different types of organic reactions: Additions Eliminations Substitutions Rearrangements 149 Addition Reactions Occur when 2 reactants
More information11/30/ Substituent Effects in Electrophilic Substitutions. Substituent Effects in Electrophilic Substitutions
Chapter 9 Problems: 9.1-29, 32-34, 36-37, 39-45, 48-56, 58-59, 61-69, 71-72. 9.8 Substituent effects in the electrophilic substitution of an aromatic ring Substituents affect the reactivity of the aromatic
More informationChapter 19: Aromatic Substitution Reactions
Chem A225 Notes Page 52 Chapter 19: Aromatic Substitution Reactions Topic One: lectrophilic Aromatic Substitution I. Introduction to lectrophilic Aromatic Substitution (AS) A. eneral Reaction Pattern B.
More informationChapter 17 Reactions of Aromatic Compounds
rganic Chemistry, 6 th Edition L. G. Wade, Jr. Chapter 17 Reactions of Aromatic Compounds Jo Blackburn Richland College, Dallas, TX Dallas County Community College District 2006, Prentice all Electrophilic
More informationChapter 10: Carboxylic Acids and Their Derivatives
Chapter 10: Carboxylic Acids and Their Derivatives The back of the white willow tree (Salix alba) is a source of salicylic acid which is used to make aspirin (acetylsalicylic acid) The functional group
More informationChapter 9 Aldehydes and Ketones Excluded Sections:
Chapter 9 Aldehydes and Ketones Excluded Sections: 9.14-9.19 Aldehydes and ketones are found in many fragrant odors of many fruits, fine perfumes, hormones etc. some examples are listed below. Aldehydes
More informationIntroduction & Definitions Catalytic Hydrogenations Dissolving Metal Reduction Reduction by Addition of H- and H+ Oxidation of Alcohols Oxidation of
CEM 241- UNIT 4 xidation/reduction Reactions Redox chemistry 1 utline Introduction & Definitions Catalytic ydrogenations Dissolving Metal Reduction Reduction by Addition of - and + xidation of Alcohols
More informationAldehydes and Ketones
9 Aldehydes and Ketones hapter Summary The carbonyl group, =, is present in both aldehydes (=) and ketones ( 2 =). The IUPA ending for naming aldehydes is -al, and numbering begins with the carbonyl carbon.
More informationmcpba e.g. mcpba (major) Section 7: Oxidation of C=X bonds
Section 7: xidation of C=X bonds Functional Group Interconversions - Lecture 6 7.1 Epoxidation of Alkenes Epoxides are VEY useful in synthesis - the strain of the three membered ring makes these cyclic
More informationAromatic Compounds II
2302272 Org Chem II Part I Lecture 2 Aromatic Compounds II Instructor: Dr. Tanatorn Khotavivattana E-mail: tanatorn.k@chula.ac.th Recommended Textbook: Chapter 17 in Organic Chemistry, 8 th Edition, L.
More informationOrganic Mechanisms 1
Organic Mechanisms 1 Concepts The key ideas required to understand this section are: Concept Book page Chemical properties of alkanes 314 Chemical properties of alkenes 318 Bonding in alkenes 320 Bonding
More informationSynthesis of Nitriles a. dehydration of 1 amides using POCl 3 : b. SN2 reaction of cyanide ion on halides:
I. Nitriles Nitriles consist of the CN functional group, and are linear with sp hybridization on C and N. Nitriles are non-basic at nitrogen, since the lone pair exists in an sp orbital (50% s character
More informationPAPER No. 5: REACTION MECHANISM MODULE No. 2: Types of Organic Reaction Mechanisms
Subject Chemistry Paper No and Title Module No and Title Module Tag Paper No. 5:Organic Chemistry-II Module No. 2: Overview of different types of Organic Reaction Mechanisms CHE_P5_M2 TABLE OF CONTENTS
More informationALCOHOLS AND PHENOLS
ALCOHOLS AND PHENOLS ALCOHOLS AND PHENOLS Alcohols contain an OH group connected to a a saturated C (sp3) They are important solvents and synthesis intermediates Phenols contain an OH group connected to
More informationKey ideas: In EAS, pi bond is Nu and undergoes addition.
Objective 7. Apply addition and elimination concepts to predict electrophilic aromatic substitution reactions (EAS) of benzene and monosubstituted benzenes. Skills: Draw structure ID structural features
More informationChem 263 Notes March 2, 2006
Chem 263 Notes March 2, 2006 Average for the midterm is 102.5 / 150 (approx. 68%). Preparation of Aldehydes and Ketones There are several methods to prepare aldehydes and ketones. We will only deal with
More informationLecture Notes Chem 51C S. King Chapter 24 Carbonyl Condensation Reactions
Lecture Notes Chem 51C S. King Chapter 24 Carbonyl Condensation Reactions I. Reaction of Enols & Enolates with ther Carbonyls Enols and enolates are electron rich nucleophiles that react with a number
More informationMCAT Organic Chemistry Problem Drill 10: Aldehydes and Ketones
MCAT rganic Chemistry Problem Drill 10: Aldehydes and Ketones Question No. 1 of 10 Question 1. Which of the following is not a physical property of aldehydes and ketones? Question #01 (A) Hydrogen bonding
More informationBasic Organic Chemistry Course code : CHEM (Pre-requisites : CHEM 11122)
Basic Organic Chemistry Course code : CHEM 12162 (Pre-requisites : CHEM 11122) Chapter 01 Mechanistic Aspects of S N2,S N1, E 2 & E 1 Reactions Dr. Dinesh R. Pandithavidana Office: B1 222/3 Phone: (+94)777-745-720
More informationKeynotes in Organic Chemistry
Keynotes in Organic Chemistry Second Edition ANDREW F. PARSONS Department of Chemistry, University of York, UK Wiley Contents Preface xi 1 Structure and bonding 1 1.1 Ionic versus covalent bonds 1 1.2
More informationAlso note here that the product is always a six membered ring with a double bond in it.
Diels Alder Class 1 March 3, 2011 I want to talk in some detail over the next few classes about Diels Alder reactions. I am sure that most of you have heard of Diels Alder reactions before, but we will
More informationPreparation of alkenes
Lecture 11 אלקנים הכנה ותגובות של אלקנים: הידרוגנציה, סיפוח הידרוהלוגנים )כלל מארקובניקוב(, סיפוח הלוגנים והסטראוכימיה של תוצרי הסיפוח, הידרובורציה, אפוקסידציה, אוזונוליזה. 1 Preparation of alkenes 1.
More informationNucleophilic Addition Reactions of Carboxylic Acid Derivatives
Lecture 5: bjectives: Nucleophilic Addition eactions of Carboxylic Acid Derivatives By the end of this lecture you will be able to: draw the mechanism of a nucleophilic addition-elimination reaction with
More informationSynthesis Using Aromatic Materials
Chapter 10 Synthesis Using Aromatic Materials ELECTROPHILIC AROMATIC SUBSTITUTION AND DIRECTED ORTHO METALATION Copyright 2018 by Nelson Education Limited 1 10.2 p Bonds Acting as Nucleophiles Copyright
More information11/26/ Polycyclic Aromatic Compounds. Polycyclic Aromatic Compounds. Polycyclic Aromatic Compounds
9.5 Polycyclic Aromatic Compounds The general concept of aromaticity can be extended to include polycyclic aromatic compounds Benzo[a]pyrene is one of the cancer-causing substances found in tobacco smoke
More informationElectrophilic Aromatic Substitution
Lecture 12 Electrophilic Aromatic Substitution E E February 22, 2018 Electrophilic Aromatic Substitution Electrophilic aromatic substitution: a reaction in which a hydrogen atom on an aromatic ring is
More informationAlcohols, Ethers and Epoxides. Chapter Organic Chemistry, 8th Edition John McMurry
Alcohols, Ethers and Epoxides Chapter 17-18 Organic Chemistry, 8th Edition John McMurry 1 Introduction Structure and Bonding Alcohols contain a hydroxy group (OH) bonded to an sp 3 hybridized carbon. 2
More informationPaper No and Title 14: Organic Chemistry IV (Advance Organic Synthesis and Supramolecular Chemistry and carbocyclic rings)
Subject Chemistry Paper No and Title 14: Organic Chemistry IV (Advance Organic Synthesis and Supramolecular Chemistry and carbocyclic Module No and 5: C-C disconnections of alcohols Title Module Tag CHE_P14_M5
More information6-2 This exercise is worked out on page 220 as "Working with Concepts".
Copyright 2009 James K Whitesell 6-1 Although we can approach this exercise from a chemical perspective, one can also teach a non-chemist how to derive the answer once the name of the starting material
More informationChapter 3 An Introduction to Organic Reactions: Acids and Bases
There are 4 types of Organic Reactions Chapter 3 An Introduction to Organic Reactions: SUBSTITUTION: ADDITION: X Y + A X A + Y Example Example A B + X Y A B X Y ELIMINATION There are 4 Types of Organic
More information75. A This is a Markovnikov addition reaction. In these reactions, the pielectrons in the alkene act as a nucleophile. The strongest electrophile will
71. B SN2 stands for substitution nucleophilic bimolecular. This means that there is a bimolecular rate-determining step. Therefore, the reaction will follow second-order kinetics based on the collision
More informationChapter 7: Alcohols, Phenols and Thiols
Chapter 7: Alcohols, Phenols and Thiols 45 -Alcohols have the general formula R-OH and are characterized by the presence of a hydroxyl group, -OH. -Phenols have a hydroxyl group attached directly to an
More informationCHEM Chapter 16. Chemistry of Benzene: Electrophilic Aromatic Substitution (homework) W
CHEM 2425. Chapter 16. Chemistry of Benzene: Electrophilic Aromatic Substitution (homework) W Short Answer Exhibit 16-1 MATCH a structure or term from the following list with each description below. Place
More informationCh 16 Electrophilic Aromatic Substitution
Ch 16 Electrophilic Aromatic Substitution Mechanism - Aromatic rings typically undergo substitution, where an H is replaced with an electrophile (E+). - The rings do not typically undergo addition across
More informationChapter 12. Reactions of Arenes: Electrophilic Aromatic Substitution. Class Notes. A. The method by which substituted benzenes are synthesized
Chapter 12 Reactions of Arenes: Electrophilic Aromatic Substitution Chapter 12 suggested problems: 22, 23, 26, 27, 32, 33 Class Notes I. Electrophilic aromatic substitution reactions A. The method by which
More informationI5 ELECTROPHILIC SUBSTITUTIONS OF
Section I Aromatic chemistry I5 ELECTPILIC SUBSTITUTINS F MN-SUBSTITUTED AMATIC INGS Key Notes ortho, meta and para substitution Substituent effect eaction profile Activating groups inductive o/p Deactivating
More informationChapter 22 Enols and Enolates
Chapter Enols and Enolates Acidity of the α hydrogen o The position next door to a carbonyl is called the α position o When an α proton is abstracted, the resulting carbanion is resonancestabilized. This
More informationOverview of Types of Organic Reactions and Basic Concepts of Organic Reaction Mechanisms
Overview of Types of Organic Reactions and Basic Concepts of Organic Reaction Mechanisms Dr. Solomon Derese 1 A chemical reaction is the transformation of one chemical or collection of chemicals into another
More informationChemistry Final Examinations Summer 2006 answers
Chemistry 235 - Final Examinations Summer 2006 answers A GEERAL CEMISTRY answers are given from 1-20: no reaction C 3 CC 3 Ph C C C C C 3 Et 2 2 2 B. REACTIS AD REAGETS [32 MARKS] 2. A single substance
More informationBut in organic terms: Oxidation: loss of H 2 ; addition of O or O 2 ; addition of X 2 (halogens).
Reactions of Alcohols Alcohols are versatile organic compounds since they undergo a wide variety of transformations the majority of which are either oxidation or reduction type reactions. Normally: Oxidation
More informationTopic 2 Alkenes and alkynes
Topic 2 Alkenes and alkynes lassification of rganic Reactions Four basic types of organic reaction Acid base reactions Substitution reactions Addition elimination reactions xidation reduction reactions
More informationMass Spectrometry. 2000, Paul R. Young University of Illinois at Chicago, All Rights Reserved
Mass Spectrometry 2000, Paul R. Young University of Illinois at Chicago, All Rights Reserved Mass Spectrometry When a molecule is bombarded with high-energy electrons, one of the process that can occur
More informationS N 1 Displacement Reactions
S N 1 Displacement Reactions Tertiary alkyl halides cannot undergo S N 2 reactions because of the severe steric hindrance blocking a backside approach of the nucleophile. They can, however, react via an
More informationChapter 22: Amines. Organic derivatives of ammonia, NH 3. Nitrogen atom have a lone pair of electrons, making the amine both basic and nucleophilic
hapter 22: Amines. rganic derivatives of ammonia, 3. itrogen atom have a lone pair of electrons, making the amine both basic and nucleophilic 22.1: Amines omenclature. (please read) sp 3 Amines are classified
More informationChemistry III (Organic): An Introduction to Reaction Stereoelectronics. LECTURE 6 1,2-Rearrangements & Fragmantations
1 Chemistry III (rganic): An Introduction to Reaction Stereoelectronics LECTURE 6 1,2-Rearrangements & Fragmantations Alan C. Spivey a.c.spivey@imperial.ac.uk Nov 2015 2 Format & scope of lecture 6 Ionic
More informationMITOCW watch?v=gboyppj9ok4
MITOCW watch?v=gboyppj9ok4 The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To
More informationOrganic Chemistry, 7 L. G. Wade, Jr. Chapter , Prentice Hall
Organic Chemistry, 7 th Edition L. G. Wade, Jr. Chapter 17 Reactions of Aromatic Compounds 2010, Prentice Hall Electrophilic Aromatic Substitution Although h benzene s pi electrons are in a stable aromatic
More informationChapter 19. Synthesis and Reactions of b-dicarbonyl Compounds: More Chemistry of Enolate Anions. ß-dicarbonyl compounds. Why are ß-dicarbonyls useful?
Chapter 19 Synthesis and Reactions of b-dicarbonyl Compounds: More Chemistry of Enolate Anions ß-dicarbonyl compounds Two carbonyl groups separated by a carbon Three common types ß-diketone ß-ketoester
More informationζ ε δ γ β α α β γ δ ε ζ
hem 263 Nov 17, 2016 eactions at the α-arbon The alpha carbon is the carbon adjacent to the carbonyl carbon. Beta is the next one, followed by gamma, delta, epsilon, and so on. 2 ε 2 δ 2 γ 2 2 β α The
More informationNuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320
Nuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320 I. Isolated, cumulated, and conjugated dienes A diene is any compound with two or C=C's is a diene. Compounds containing more than two
More information8.8 Unimolecular Nucleophilic Substitution S N 1
8.8 Unimolecular Nucleophilic Substitution S N 1 A question. Tertiary alkyl halides are very unreactive in substitutions that proceed by the S N 2 mechanism. Do they undergo nucleophilic substitution at
More informationChapter 20 Carboxylic Acid Derivatives Nucleophilic Acyl Substitution
Chapter 20 Carboxylic Acid Derivatives Nucleophilic Acyl Substitution Nomenclature: In carboxylic acid chlorides, anhydrides, esters and amides, the parent is the carboxylic acid. In each case be sure
More informationStructure and Preparation of Alkenes: Elimination Reactions
Structure and Preparation of Alkenes: Elimination Reactions Alkene Nomenclature First identify the longest continuous chain that includes the double bond. Replace the -ane ending of the corresponding unbranched
More informationAllylic and Benzylic Reactivity
17 17 Allylic and Benzylic Reactivity An allylic group is a group on a carbon adjacent to a double bond. A benzylic group is a group on a carbon adjacent to a benzene ring or substituted benzene ring.
More informationChapter 8 Alkenes and Alkynes II: Addition Reactions. Alkenes are electron rich. Additions to Alkenes
Additions to Alkenes Chapter 8 Alkenes and Alkynes II: Addition Reactions Generally the reaction is exothermic because one p and one s bond are converted to two s bonds Alkenes are electron rich The carbocation
More informationTHE CHEMISTRY OF THE CARBONYL GROUP
TE CEMISTY F TE CABYL GUP Professor Tim Donohoe 8 lectures, T, weeks 1-4, 2007 andout A C C You will be able to download copies of the handouts from this course at http://users.ox.ac.uk/~magd1571/teaching/teaching.htm
More informationOrganic Chemistry. Organic Reactions
For updated version, please click on http://ocw.ump.edu.my Organic Chemistry Organic Reactions by Dr. Seema Zareen & Dr. Izan Izwan Misnon Faculty Industrial Science & Technology seema@ump.edu.my & iezwan@ump.edu.my
More informationCHE1502. Tutorial letter 201/1/2016. General Chemistry 1B. Semester 1. Department of Chemistry CHE1502/201/1/2016
CE1502/201/1/2016 Tutorial letter 201/1/2016 General Chemistry 1B CE1502 Semester 1 Department of Chemistry This tutorial letter contains the answers to the questions in assignment 1. FIRST SEMESTER: KEY
More informationLoudon Chapter 10 Review: Alcohols & Thiols Jacquie Richardson, CU Boulder Last updated 4/26/2016
Alcohols (R) and thiols (RS) have many reactions in common with alkyl halides, but they don t do everything exactly the same. The main difference between this and alkyl halide chemistry is that unlike
More informationChapter 8. Substitution reactions of Alkyl Halides
Chapter 8. Substitution reactions of Alkyl Halides There are two types of possible reaction in organic compounds in which sp 3 carbon is bonded to an electronegative atom or group (ex, halides) 1. Substitution
More informationAlcohols, Ethers, & Epoxides
Alcohols, Ethers, & Epoxides Alcohols Structure and Bonding Enols and Phenols Compounds having a hydroxy group on a sp 2 hybridized carbon enols and phenols undergo different reactions than alcohols. Chapter
More informationElectrophile = electron loving = any general electron pair acceptor = Lewis acid, (often an acidic proton)
314 Arrow Pushing practice/eauchamp 1 Electrophile = electron loving = any general electron pair acceptor = Lewis acid, (often an acidic proton) ucleophile = nucleus/positive loving = any general electron
More informationLecture 3: Aldehydes and ketones
Lecture 3: Aldehydes and ketones I want to start by talking about the mechanism of hydroboration/ oxidation, which is a way to get alcohols from alkenes. This gives the anti-markovnikov product, primarily
More informationElectrophilic Aromatic Substitution
Chem 263 ct. 8, 2013 lectrophilic Aromatic Substitution Benzene appears to be a remarkably stable and unreactive compared to alkenes, such as cyclohexene or ethylene, or even alkanes, such as cyclohexane
More informationORGANIC - CLUTCH CH ADDITION REACTIONS.
!! www.clutchprep.com CONCEPT: GENERAL MECHANISM Addition reactions are ones in which 1 bond is broken and 2 new bonds are formed. They are the inverse of reactions EXAMPLE: Provide the mechanism for the
More information(Neither an oxidation or reduction: Addition or loss of H +, H 2 O, HX).
eactions of Alcohols Alcohols are versatile organic compounds since they undergo a wide variety of transformations the majority of which are either oxidation or reduction type reactions. xidation is a
More informationAldehydes and Ketones: Nucleophilic Addition Reactions
Aldehydes and Ketones: Nucleophilic Addition Reactions Why this Chapter? Much of organic chemistry involves the chemistry of carbonyl compounds Aldehydes/ketones are intermediates in synthesis of pharmaceutical
More informationOAT Organic Chemistry - Problem Drill 19: NMR Spectroscopy and Mass Spectrometry
OAT Organic Chemistry - Problem Drill 19: NMR Spectroscopy and Mass Spectrometry Question No. 1 of 10 Question 1. Which statement concerning NMR spectroscopy is incorrect? Question #01 (A) Only nuclei
More informationChapter 20 Carboxylic Acid Derivatives. Nucleophilic Acyl Substitution
ucleophilic Acyl Substitution hapter 20 arboxylic Acid Derivatives ucleophilic Acyl Substitution Y (1) need to have Y as a u Y u u + Y (2) could not happen with aldehydes or ketones as : and : are poor
More information