Elimination reactions
|
|
- Theresa Mathews
- 5 years ago
- Views:
Transcription
1 Chapter 9 Elimination reactions E2 and E1 reactions Competition between S N and E
2 Elimination reactions Ch 9 #2 elimination and/or substitution 2 mechanisms ~ E2 and E1
3 E2: bimolecular elimination rxn bimolecular mechanism ~ concerted Ch 9 #3 no substitution? 1,2-elimination or β-elimination leaving group effect
4 E2: regioselectivity (1) ~ Zaitsev s rule Ch 9 #4 Zaitsev s rule The more substituted alkene product is obtained when a proton is removed from the β-carbon that is bonded to the fewest hydrogens. a product [thermodynamic] control
5 Ch 9 #5 Generally, 1 > 2 (no 3 ) for S N 2 Nu: attacks C 3 > 2 > 1 for E2 (and E1, except 1 ) B: attacks [takes] H
6 E2: regioselectivity (2) ~ resonance Ch 9 #6 Resonance-stabilized alkene [conjugated diene] is more stable. It may not be the more-substituted.
7 E2: regioselectivity (3) ~ steric Ch 9 #7
8 E2: regioselectivity (4) ~ leaving group Ch 9 #8 F is the poorest leaving group. alkene-like TS carbanion-like TS
9 Ch 9 #9 stability of carbanion Effect of leaving group on E2 product Major product of E2 rxn is the more stable alkene. exceptions ~ steric reactant(s), (very) poor leaving group
10 E1: unimolecular elimination reaction Ch 9 #10 unimolecular mechanism no substitution? weak base takes H from sp 3 C? C + accepts e of C: + hyperconjugation
11 E1: reactivity Ch 9 #11 C + stability trend same to SN1 trend same to E2 leaving group effect trend same to S N 2, S N 1, and E2
12 E1: regioselectivity Ch 9 #12 more substituted product ~ Zaitsev s rule
13 E1: C + rearrangement Ch 9 #13
14 Competition betw E2 and E1 Ch 9 #14 E2 is favored by (high concentration of) strong base (like HO, RO ), and in aprotic polar solvent (like DMF, DMSO). E1 is favored by weak base (like H 2 O, ROH), and in protic polar solvent (like H 2 O, ROH). S N 2 is favored by good Nu: in aprotic polar solvent. S N 1 is favored by poor Nu: in protic polar solvent.
15 Stereochemistry of E2 and E1 Ch 9 #15 E2 is an anti-elimination rxn. 4 atoms [H, C, C, X] must be periplanar [coplanar] to form C=C double bond. anti-periplanar (highly) favored over syn-periplanar
16 Ch 9 #16 E2 is stereoselective when 2 β-h s 2 products (stereoselective)
17 Ch 9 #17 when 1 β-h 1 product stereospecific? (2R,3S)?
18 Ch 9 #18 E1 also is stereoselective. 2 β-h s 2 products (stereoselective) 1 β-h s 2 products (stereoselective)
19 Elimination from substituted cx Ch 9 #19 E2 must be anti-periplanar. H and X must be trans-diaxial. E2 of menthyl chloride is slow.
20 Ch 9 #20 + E2 of neomenthyl chloride is rather fast.
21 Ch 9 #21 E1 need not be periplanar. + Cl CH 3 OH CH 3 O 2 S N + 2 E products 1 product
22 Stereochemistry of S N and E Ch 9 #22
23 Kinetic isotope effect Ch 9 #23 k H = 7.1 k D C D stronger than C H (why?) (deuterium) kinetic isotope effect = k H /k D = 7.1 supports E2 (concerted) mechanism, not E1
24 Competition betw S N and E Ch 9 #24 S N 2/E2 is favored by good Nu:/strong B: in aprotic polar solvent. S N 1/E1 is favored by poor Nu:/weak B: in protic polar solvent. X X X S N 2/E favors S N 2 over E2. why? above comparison? just observed.
25 Ch 9 #25 S N 2/E2 (cont d) 2. Steric hindrance favors E2 over S N 2.
26 Ch 9 #26 S N 2/E2 (cont d) 3. Stronger B: [Nu:] favors E2 over S N 2. why? just observed. RCOO ~ a medium base H 3 O + > RCOOH > H 2 O
27 Ch 9 #27 S N 2/E2 (cont d) 4. High temperature favors E2 over S N 2. why? T S
28 Ch 9 #28 S N 2/E2 (cont d) 5. 3 undergoes E2 only.
29 Ch 9 #29 S N 1/E1 hard to control the ratio of S N 1 to E1 no S N 1/E1 for 1 more S N 1 over E1 for 3 why? no S N 2 for 3? just observed.
30 Ch 9 #30
31 Using S N in synthesis Ch 9 #31 Williamson (ether) synthesis S N 2 preparation of RO need very strong base for alcohol need less strong base for phenol
32 Ch 9 #32 Williamson (ether) synthesis (cont d) Substrate [RX] should be 1. no S N, no ether (b) is (much) better (a) gives E2 product also S N 1 (using ROH) for 2 or 3 substrate
33 Ch 9 #33 alkynes from acetylide ion S N 2 Substrate [RX] better be 1.
34 Using E in synthesis Ch 9 #34 preparation of alkene E2(/S N 2) rather than E1(/S N 1) 2 better, more hindered better more E2 by using t-buo instead of OH, high temperature
35 Ch 9 #35 preparation of alkyne from dihalides need very strong base ( NH 2 > OH) vinyl halide from alkene
36 Designing synthesis II Ex 1> pka of HCN = 9.1 Ch 9 #36 direct hydrocyanation? possible, using catalyst using S N /E Ex 2> CN ~ stronger B: than Br, weaker B: than OH S N 2 over E2 (or maybe S N 1/E1) E2, no S N 2 anti-markovnikov, syn
37 Ch 9 #37 Ex 3> E2, no S N 2 Ex 4> not BH 3 not BH 3 S N 2 (low E2)
Dehydrohalogenation of Alkyl Halides E2 and E1 Reactions in Detail
Dehydrohalogenation of Alkyl Halides E2 and E1 Reactions in Detail b-elimination Reactions Overview dehydration of alcohols: X = H; Y = OH dehydrohalogenation of alkyl halides: X = H; Y = Br, etc. X C
More informationReactions of Alkyl Halides with Nucleophiles and Bases a substitution reaction
Reactions of Alkyl Halides with Nucleophiles and Bases a substitution reaction Nucleophilic substitution and base induced elimination are among most widely occurring and versatile reaction types in organic
More informationWalden discovered a series of reactions that could interconvert (-)-malic acid and (+)-malic acid.
Chapter 11: Reactions of alkyl halides: nucleophilic substitutions and eliminations Alkyl halides are polarized in the C-X bond, making carbon δ+ (electrophilic). A nucleophilecan attack this carbon, displacing
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 informationSubstitution and Elimination reactions
PART 3 Substitution and Elimination reactions Chapter 8. Substitution reactions of RX 9. Elimination reactions of RX 10. Substit n/elimin n of other comp ds 11. Organometallic comp ds 12. Radical reactions
More informationChapter 8 Alkyl Halides and Elimination Reactions
Organic Chemistry, Second Edition Janice Gorzynski Smith University of Hawai i Chapter 8 Alkyl Halides and Elimination Reactions Prepared by Rabi Ann Musah State University of New York at Albany Copyright
More informationNucleophilic Substitution and Elimination
Nucleophilic Substitution and Elimination Alkyl halides react with a nucleophile in one of two ways. Either they eliminate an X to form an alkene, or they undergo a substitution with the nucleophile, Nu,
More informationChapter 9. Nucleophilic Substitution and ß-Elimination
Chapter 9 Nucleophilic Substitution and ß-Elimination Nucleophilic Substitution Nucleophile: From the Greek meaning nucleus loving. A molecule or ion that donates a pair of electrons to another atom or
More informationEssential Organic Chemistry. Chapter 9
Essential Organic Chemistry Paula Yurkanis Bruice Chapter 9 Substitution and Elimination Reactions of Alkyl Halides 9.1 How Alkyl Halides React Substitution Reactions One group takes the place of another.
More informationDr. Anand Gupta Mr Mahesh Kapil
Dr. Anand Gupta Mr Mahesh Kapil 09356511518 09888711209 anandu71@yahoo.com mkapil_foru@yahoo.com Preparation of Haloalkanes From Alkanes Alkenes Alcohols Carboxylic Acids (Hundsdicker Reaction) Halide
More informationCHAPTER 7. Further Reactions of Haloalkanes: Unimolecular Substitution and Pathways of Elimination
CHAPTER 7 Further Reactions of Haloalkanes: Unimolecular Substitution and Pathways of Elimination 7-1 Solvolysis of Tertiary and Secondary Haloalkanes The rate of S N 2 reactions decrease dramatically
More information+ + CH 11: Substitution and Elimination Substitution reactions
C 11: Substitution and Elimination Substitution reactions Things to sort out: Nucleophile Electrophile -- > substrate Leaving Group S N 2 S N 1 E 1 E 2 Analysis Scheme Kinetics Reaction profile Substrates
More informationOrganic Reactions Susbstitution S N. Dr. Sapna Gupta
Organic Reactions Susbstitution S N 2 Dr. Sapna Gupta Kinetics of Nucleophilic Reaction Rate law is order of reaction 0 order is when rate of reaction is unaffected by change in concentration of the reactants
More informationChapter 11, Part 1: Polar substitution reactions involving alkyl halides
hapter 11, Part 1: Polar substitution reactions involving alkyl halides Overview: The nature of alkyl halides and other groups with electrophilic sp 3 hybridized leads them to react with nucleophiles and
More informationElimination Reactions. Chapter 6 1
Elimination Reactions Chapter 6 1 E1 Mechanism Step 1: halide ion leaves, forming a carbocation. Step 2: Base abstracts H + from adjacent carbon forming the double bond. Chapter 6 2 E1 Energy Diagram E1:
More information10. Organohalides. Based on McMurry s Organic Chemistry, 7 th edition
10. Organohalides Based on McMurry s Organic Chemistry, 7 th edition What Is an Alkyl Halide An organic compound containing at least one carbonhalogen bond (C-X) X (F, Cl, Br, I) replaces H Can contain
More information1. Radical Substitution on Alkanes. 2. Radical Substitution with Alkenes. 3. Electrophilic Addition
1. Radical Substitution on Alkanes Only Cl and Br are useful at the laboratory level. Alkane reactivity: tertiary > secondary > primary > methyl Numbers below products give their relative yield. Relative
More informationAdditions to the Carbonyl Groups
Chapter 18 Additions to the Carbonyl Groups Nucleophilic substitution (S N 2andS N 1) reaction occurs at sp3 hybridized carbons with electronegative leaving groups Why? The carbon is electrophilic! Addition
More informationClasses of Alkenes. Alkenes and Alkynes. Saturated compounds (alkanes): Have the maximum number of hydrogen atoms attached to each carbon atom.
Alkenes and Alkynes Saturated compounds (alkanes): ave the maximum number of hydrogen atoms attached to each carbon atom. Unsaturated compounds: ave fewer hydrogen atoms attached to the carbon chain than
More informationC h a p t e r S e v e n : Haloalkanes: Nucleophilc Substitution and Elimination Reactions S N 2
C h a p t e r S e v e n : Haloalkanes: Nucleophilc Substitution and Elimination Reactions S N 2 CHM 321: Summary of Important Concepts Concepts for Chapter 7: Substitution Reactions I. Nomenclature of
More informationREACTION AND SYNTHESIS REVIEW
REACTION AND SYNTHESIS REVIEW A STUDENT SHOULD BE ABLE TO PREDICT PRODUCTS, IDENTIFY REACTANTS, GIVE REACTION CONDITIONS, PROPOSE SYNTHESES, AND PROPOSE MECHANISMS (AS LISTED BELOW). REVIEW THE MECHANISM
More informationOrganic Chemistry CHM 314 Dr. Laurie S. Starkey, Cal Poly Pomona Alkyl Halides: Substitution Reactions - Chapter 6 (Wade)
rganic Chemistry CM 314 Dr. Laurie S. Starkey, Cal Poly Pomona Alkyl alides: Substitution Reactions - Chapter 6 (Wade) Chapter utline I. Intro to RX (6-1 - 6-7) II. Substitution Reactions A) S N 2 (6-8,
More informationOrganic Reactions Susbstitution S N. Dr. Sapna Gupta
Organic Reactions Susbstitution S N 2 Dr. Sapna Gupta Kinetics of Nucleophilic Reaction Rate law is order of reaction 0 order is when rate of reaction is unaffected by change in concentration of the reactants
More informationChapter 8 Outline: Alkenes: Structure and Preparation via β-elimination
Chapter 8 Outline: Alkenes: Structure and Preparation via β-elimination 1. What is β elimination? 2. Alkenes: structure, steroisomerism and stability 3. Elimination Reactions o E2 Mechanism o E1 Mechanism
More informationElimination Reactions The E2 Mechanism
Elimination Reactions The E2 Mechanism The E2 Mechanism X X- B: B- δ- B:- δ+ R 1 δ- R 2 δ+ X δ- The E2 Mechanism R 3 R 4 transition state Free energy (G) Eact B:- B R 1 R 2 X R 1 R 2 R 3 R 4 R 4 R 3 X:-
More informationElimination Reactions The E2 Mechanism
Elimination Reactions The E2 Mechanism The E2 Mechanism X B: δ- B:- δ+ R 1 C δ- R 2 C δ+ X δ- The E2 Mechanism R 3 R 4 transition state Free energy (G) Eact B:- B R 1 R 2 C C X R 1 R 2 R 3 R 4 R 4 R 3
More informationc. Cl H Page 1 of 7 major P (E > Z and more substituted over less substituted alkene) LG must be axial are the same Cl -
CEM 109A 1. Predict the products of the following reactions (a-c E2, d-f E1 KEY focuses only on elimination products, in most cases there will also be substitution products.) a. - LG must be axial - are
More informationGlendale Community College Chemistry 105 Exam. 3 Lecture Notes Chapters 6 & 7
Sevada Chamras, Ph.D. Glendale Community College Chemistry 105 Exam. 3 Lecture Notes Chapters 6 & 7 Description: Examples: 3 Major Types of Organic Halides: 1. Alkyl Halides: Chapter 6 (Part 1/2) : Alkyl
More information11. Reactions of Alkyl Halides: Nucleophilic Substitutions and Eliminations
11. Reactions of Alkyl Halides: Nucleophilic Substitutions and Eliminations Based on McMurry s Organic Chemistry, 6 th edition 2003 Ronald Kluger Department of Chemistry University of Toronto Alkyl Halides
More informationChapter 6 Ionic Reactions-Nucleophilic Substitution and Elimination Reactions of Alkyl Halides"
Chapter 6 Ionic Reactions-Nucleophilic Substitution and Elimination Reactions of Alkyl Halides" t Introduction" The polarity of a carbon-halogen bond leads to the carbon having a partial positive charge"
More informationChapter 11: Nucleophilic Substitution and Elimination Walden Inversion
hapter 11: Nucleophilic Substitution and Elimination Walden Inversion (S)-(-) Malic acid [a] D = -2.3 Ag 2, 2 Pl 5 l Ag 2, 2 ()-2-hlorosuccinic acid l (-)-2-hlorosuccinic acid Pl 5 ()-() Malic acid [a]
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 informationPreparation of Alkyl Halides, R-X. Reaction of alkanes with Cl 2 & Br 2 (F 2 is too reactive, I 2 is unreactive): R + X X 2.
Preparation of Alkyl alides, R-X Reaction of alkanes with Cl 2 & Br 2 (F 2 is too reactive, I 2 is unreactive): UV R + X 2 R X or heat + X This mechanism involves a free radical chain reaction. A chain
More informationChem 251 Fall Learning Objectives
Learning Objectives Chapter 8 (last semester) 1. Write an electron-pushing mechanism for an SN2 reaction between an alkyl halide and a nucleophile. 2. Describe the rate law and relative rate of reaction
More informationAlkyl Halides. Alkyl halides are a class of compounds where a halogen atom or atoms are bound to an sp 3 orbital of an alkyl group.
Alkyl Halides Alkyl halides are a class of compounds where a halogen atom or atoms are bound to an sp 3 orbital of an alkyl group. CHCl 3 (Chloroform: organic solvent) CF 2 Cl 2 (Freon-12: refrigerant
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 informationOrganic Chemistry The Functional Group Approach. Organic Chemistry The Functional Group Approach
Organic Chemistry The Functional Group Approach OH Br alkane (no F.G.) alcohol halide alkene non-polar (grease, fats) O NH alkyne aromatic aldehyde/ketone imine linear flat Organic Chemistry The Functional
More informationChapter 4. Reactions of alkenes. Addition reactions Carbocations Selectivity of reactions
Chapter 4 Reactions of alkenes Addition reactions Carbocations Selectivity of reactions Prob 47 p192. Give the reagents that would be required (including catalyst). Ch 4 #2 Electrophilic addition Ch 4
More informationORGANIC - CLUTCH CH. 8 - ELIMINATION REACTIONS.
!! www.clutchprep.com CONCEPT: THE E2 MECHANISM A strong nucleophile reacts with an inaccessible leaving group to produce beta-elimination in one-step. E2 Properties (Circle One) Nucleophile = Strong /
More informationOChem 1 Mechanism Flashcards. Dr. Peter Norris, 2018
OChem 1 Mechanism Flashcards Dr. Peter Norris, 2018 Mechanism Basics Chemical change involves bonds forming and breaking; a mechanism describes those changes using curved arrows to describe the electrons
More informationREACTIONS OF HALOALKANES - SUBSTITUTION AND ELIMINATION
REACTIONS OF HALOALKANES - SUBSTITUTION AND ELIMINATION Haloalkanes (also known as halogenoalkanes and alkyl halides) are organic compounds where one of the hydrogens of an alkane or cycloalkane has been
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 7 Substitution Reactions 7.1 Introduction to Substitution Reactions Substitution Reactions: two reactants exchange parts to give new products
hapter 7 Substitution eactions 7.1 Introduction to Substitution eactions Substitution eactions: two reactants exchange parts to give new products A-B + -D A-D + B- 3 2 + Br 3 2 Br + Elimination eaction:
More informationHow alkyl halides react
Chapter 10 1 How alkyl halides react δ+ δ- RCH 2 -X X= halogen X = higher EN C = lower EN This polar carbon-halogen bond causes alkyl halide to undergo S N and elimination reaction. 2 The mechanism of
More informationC h a p t e r E i g h t: Alkenes: Structure and Preparation via Elimination Reactions. 5-Androstene, the parent alkene for most anabolic steroids
C h a p t e r E i g h t: Alkenes: Structure and Preparation via Elimination Reactions 5-Androstene, the parent alkene for most anabolic steroids CHM 321: Summary of Important Concepts YConcepts for Chapter
More informationElimination Reactions:
Elimination Reactions: These are just reverse of addition reactions. These involve the removal of atoms or group of atoms from a molecule. Elimination reactions are generally endothermic and take place
More informationOChem 1 Mechanism Flashcards. Dr. Peter Norris, 2015
OChem 1 Mechanism Flashcards Dr. Peter Norris, 2015 Mechanism Basics Chemical change involves bonds forming and breaking; a mechanism describes those changes using curved arrows to describe the electrons
More informationSn1 or Sn2 Reactions: A Guide to Deciding Which Reaction is Occurring
Sn1 or Sn2 Reactions: A Guide to Deciding Which Reaction is Occurring The following is a discussion of the approach you should use in order to determine if a chemical reaction occurs via a Sn1 or Sn2 mechanism.
More informationChapter 8: Nucleophilic Substitution 8.1: Functional Group Transformation By Nucleophilic Substitution
hapter 8: Nucleophilic Substitution 8.1: Functional Group Transformation By Nucleophilic Substitution Nu: = l,, I Nu - Nucleophiles are Lewis bases (electron-pair donor) Nucleophiles are often negatively
More informationChapter 5. Nucleophilic aliphatic substitution mechanism. by G.DEEPA
Chapter 5 Nucleophilic aliphatic substitution mechanism by G.DEEPA 1 Introduction The polarity of a carbon halogen bond leads to the carbon having a partial positive charge In alkyl halides this polarity
More informationReaction mechanism 1/17/19. HCl. HCl. 3 radical can form here. Br 2. hint!
If the reagents or reaction conditions favor radicals, then it is likely to be a radical reaction. Look for hints like peroxide, AIBN, NBS, hn (UV light). 3 radical can form here Reaction mechanism How
More informationHomework problems Chapters 6 and Give the curved-arrow formalism for the following reaction: CH 3 OH + H 2 C CH +
omework problems hapters 6 and 7 1. Give the curved-arrow formalism for the following reaction: : 3 - : 2 : 3 2-3 3 2. In each of the following sets, arrange the compounds in order of decreasing pka and
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 informationCONCERTED sp 2 H. HO Et
Alkyl alides Substitution and Elimination 1 Substitutions (Quick Review) 1.1 SN2 Reactions LB nucleophile "backside attack!" NERTED reaction This is fundamentally just a Lewis acid/base reaction, the Lewis
More informationORGANIC - EGE 5E CH. 7 - NUCLEOPHILIC SUBSTITUTION AND ELIMINATION REACTIONS
!! www.clutchprep.com CONCEPT: INTRODUCTION TO SUBSTITUTION Previously, we discussed the various ways that acids could react with bases: Recall that in these mechanisms, electrons always travel from density
More informationChapter 7 Alkenes and Alkynes I: Properties and Synthesis Elimination Reactions of Alkyl Halides"
Chapter 7 Alkenes and Alkynes I: Properties and Synthesis Elimination Reactions of Alkyl Halides The (E)-(Z) System for Designating Alkene Diastereomers The Cahn-Ingold-Prelog convention is used to assign
More informationElimination Reactions Heating an alkyl halide with a strong base causes elimination of a. molecule of HX
Elimination eactions eating an alkyl halide with a strong base causes elimination of a molecule of X 1. Potassium hydroxide dissolved in ethanol and the sodium salts of alcohols (such as sodium ethoxide)
More informationOnly five of the molecules below may be prepared as the sole product of allylic halogenation of the respective alkene. Circle those five.
Chem 232 D. J. Wardrop wardropd@uic.edu Problem Set 6 Answers Question 1. nly five of the molecules below may be prepared as the sole product of allylic halogenation of the respective alkene. Circle those
More information7. Haloalkanes (text )
2009, Department of hemistry, The University of Western Ontario 7.1 7. aloalkanes (text 7.1 7.10) A. Structure and Nomenclature Like hydrogen, the halogens have a valence of one. Thus, a halogen atom can
More informationChapter 8: Alkene Structure and Preparation via Elimination Reactions
Nature of the pi bond Chapter 8: Alkene Structure and Preparation via Elimination eactions [Sections: 8.1-8.13] C C 3 C C 3 bond length bond strength 2 C C 2 a C=C double bond is stronger than a C C single
More information2/26/18. Practice Questions. Practice Questions B F. How many steps are there in this reaction?
Practice Questions Practice Questions D B F C E A G How many steps are there in this reaction? 1 Practice Questions D B F C E A G What is the highest-energy transitions state? Practice Questions D B F
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 informationClasses of Halides. Chapter 6 Alkyl Halides: Nucleophilic Substitution and Elimination. Polarity and Reactivity. Classes of Alkyl Halides
rganic hemistry, 5 th Edition L. G. Wade, Jr. hapter 6 Alkyl alides: Nucleophilic Substitution and Elimination lasses of alides Alkyl: alogen, X, is directly bonded to sp 3 carbon. Vinyl: X is bonded to
More information1/4/2011. Chapter 18 Aldehydes and Ketones Reaction at the -carbon of carbonyl compounds
Chapter 18 Aldehydes and Ketones Reaction at the -carbon of carbonyl compounds The Acidity of the Hydrogens of Carbonyl Compounds: Enolate Anions Hydrogens on carbons to carbonyls are unusually acidic
More information1-What is substitution reaction? 2-What are can Nucleophilic Substitution Reaction? 3- SN1 reaction. 4-SN2 reaction 5- mechanisms of SN1&SN2
1-What is substitution reaction? 2-What are can Nucleophilic Substitution eaction? 3- SN1 reaction. 4-SN2 reaction 5- mechanisms of SN1&SN2 1- SUBSTITUTION EACTIONS 1-Substitution eaction In this type
More informationCHEM 263 Oct 25, stronger base stronger acid weaker acid weaker base
CEM 263 ct 25, 2016 Reactions and Synthesis (Preparation) of R- Breaking the - Bond of R- with Metals R + Li 0 or Na 0 or K 0 metal R Li + 1/2 2 alkoxide Breaking the - Bond of R- by Acid-Base Reaction
More informationChapter 6: Organic Halogen Compounds; Substitution and Elimination Reactions
Chapter 6: Organic Halogen Compounds; Substitution and Elimination Reactions Halogen compounds are important for several reasons. Simple alkyl and aryl halides, especially chlorides and bromides, are versatile
More informationAcid-Base -Bronsted-Lowry model: -Lewis model: -The more equilibrium lies to the right = More [H 3 O + ] = Higher K a = Lower pk a = Stronger acid
Revision Hybridisation -The valence electrons of a Carbon atom sit in 1s 2 2s 2 2p 2 orbitals that are different in energy. It has 2 x 2s electrons + 2 x 2p electrons are available to form 4 covalent bonds.
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 informationChapter 8: Alkene Structure and Preparation via Elimination Reactions
1. Nature of the pi bond Chapter 8: Alkene Structure and Preparation via Elimination eactions [Sections: 8.1-8.13] C C bond length bond strength 3 C C 3 3 C C 3 3 C C 3 3 C 2 C C 2 3 C a C=C double bond
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 informationObjective 11. Apply Reactivity Principles to Substitution and Elimination Reactions: compare size and strength of nucleophile to predict major product
Objective 11 Apply Reactivity Principles to Substitution and Elimination Reactions: compare size and strength of nucleophile to predict major product Given Reactants ----> Predict Products How to figure
More informationUCF - ORGANIC CHEMISTRY 1 - PROF. DAOUDI UCF PROF. DAOUDI EXAM 3 REVIEW.
UCF PROF. DAOUDI EXAM 3 REVIEW www.clutchprep.com 1 PRACTICE: Identify the most stable and the least stable alkene PRACTICE: Create the full arrow pushing mechanism which shows all intermediates and all
More informationChem 3719 Example Exams. Chemistry 3719 Practice Exams
Chem 3719 Example Exams Chemistry 3719 Practice Exams Fall 2018 Chemistry 3719, Fall 2017 Exam 1 Student Name: Y Number: This exam is worth 100 points out of a total of 700 points for Chemistry 3719/3719L.
More informationC h a p t e r S e v e n : Substitution Reactions S N 2 O H H H O H H. Br -
C h a p t e r S e v e n : Substitution Reactions Br Br S N 2 CM 321: Summary of Important Concepts YConcepts for Chapter 7: Substitution Reactions I. Nomenclature of alkyl halides, R X A. Common name:
More informationAlkenes are prepared by the reverse of the electrophilic reactions in the last chapter. That is, they are prepared by elimination reactions.
Ch 8 Alkene Reactions and Syntheses Alkenes are prepared by the reverse of the electrophilic reactions in the last chapter. That is, they are prepared by elimination reactions. Dehydrohalogenation - Mechanism
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 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 Notes Chem 51B S. King I. Conjugation
Lecture Notes Chem 51B S. King Chapter 16 Conjugation, Resonance, and Dienes I. Conjugation Conjugation occurs whenever p-orbitals can overlap on three or more adjacent atoms. Conjugated systems are more
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 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 information1.13 Acid-Base Reactions: Lone-Pair Donors & Acceptors
1.13 Acid-Base Reactions: Lone-Pair Donors & Acceptors I, Cl, N 3, 3 P 4 pka 10 to 5 Super strong acids 3 + pka 1.7 RC 2 pka ~ 5 acids Ph pka ~ 10 get 2, R pka ~ 16 weaker RCC (alkynes) pka ~ 26 RN 2 pka
More informationAlkyl Halides and Nucleophilic Subs5tu5on Reac5ons. S N 2 and S N 1 Reac,ons
Alkyl Halides and Nucleophilic Subs5tu5on Reac5ons S N 2 and S N 1 Reac,ons 1 Alkyl Halides The electronega5ve halogen atom in alkyl halides creates a polar C X bond, making the carbon atom electron deficient.
More information2311A and B Practice Problems to help Prepare for Final from Previous Marder Exams.
2311A and B Practice Problems to help Prepare for Final from Previous Marder Exams. Disclaimer.: Use only to help learn what you need to know and don t expect the final to be in the same form. 1 1. Short
More informationThe Electrophile. S N 2 and E2 least stable most stable least hindered most hindered. S N 1 and E1. > x > >
The Electrophile 1 Recall that electrophile means electron- loving. When considering substitution and elimination reactions we must consider the carbon attached to the leaving group. Is it a primary, secondary,
More informationPhysical Properties: Structure:
Nomenclature: Functional group suffix = -ol Functional group prefix = hydroxy- Primary, secondary or tertiary? Alcohols are described as primary (1 o ), secondary (2 o ) or tertiary (3 o ) depending on
More informationChapter 8 I. Nucleophilic Substitution (in( II. Competion with Elimination. Nucleophilic Substitution
hapter 8 I. Nucleophilic Substitution (in( depth) II. ompetion with Elimination Nucleophilic Substitution Substrate is a sp3 hybridized carbon atom (cannot be an a vinylic halide or an aryl halide except
More informationLECTURE #14 Thurs., Oct.20, Midterm exam: Tues.Oct.25 during class Ch.1, , 7.10, 2, Sections
CHEM 221 section 01 LECTURE #14 Thurs., Oct.20, 2005 Midterm exam: Tues.Oct.25 during class Ch.1, 7.2-7.5, 7.10, 2, 3.1-3.5 ASSIGNED READINGS: TODAY S CLASS: NEXT LECTURE: Sections 4.7-4.10 finish Ch.4,
More informationChapter 9 Alkynes. Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 9 Alkynes Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9.1 Sources of Alkynes Acetylene Industrial preparation of acetylene is by dehydrogenation of
More informationChapter 7 - Alkenes and Alkynes I
Andrew Rosen Chapter 7 - Alkenes and Alkynes I 7.1 - Introduction - The simplest member of the alkenes has the common name of ethylene while the simplest member of the alkyne family has the common name
More informationLoudon Chapter 9 Review: Reactions of Alkyl Halides Jacquie Richardson, CU Boulder Last updated 5/1/2016
Chapter 9 covers reactions you can do with alkyl halides. For the most part, these break down into two categories: substitution and elimination. Substitution results in replacing the halogen with some
More informationChapter 11 - Alcohols and Ethers 1
Andrew Rosen Chapter 11 - Alcohols and Ethers 1 11.1 - Structure and Nomenclature - The common naming calls alcohols as alkyl alcohols (eg: methyl alcohol) - The common names of ethers have the groups
More information9.2 Bimolecular Elimination
314 CAPTE 9 ELIMINATION EACTIONS called carbon 1, then the proton is lost from carbon 2 The reaction is therefore termed a 1,2-elimination (Alternatively, because the carbon attached to the functional
More informationCHEMISTRY. Module No and Title Module-7, Nucleophilic and Free Radical Addition. Reactions of Alkenes
Subject Chemistry Paper No and Title Paper-9, Organic Chemistry-III (Reaction Mechanism-2) Module No and Title Module-7, Nucleophilic and Free Radical Addition Module Tag CHE_P9_M7 TABLE OF CONTENTS 1.
More information1. The Substrate: CH3, 1 o, 2 o, 3 o, Allyl or Benzyl
Putting it all together: Substitution and elimination reactions are almost always in competition with each other. In order to predict the products of a reaction, it is necessary to determine which mechanisms
More informationChapter 15: Conjugated Systems, Orbital Symmetry, and UV Spectroscopy
Chapter 15: Conjugated Systems, Orbital Symmetry, and UV Spectroscopy Conjugated unsaturated systems have a p orbital on a carbon adjacent to a double bond The p orbital can come from another double (e.g.
More informationSubstitution α to a carbonyl center: Enol and enolate chemistry
Chapter 11 Organic Reaction Mechanisms, Part 2: Substitutions at Aliphatic Centers and Thermal Isomerizations/Rearrangements 11.1 Tautomerization Substitution α to a carbonyl center: Enol and enolate chemistry
More informationAlkyl Halides React with Nucleophiles and Bases
Chapter 11- Reactions of Alkyl Halides: Nucleophilic Substitutions and Eliminations Ashley Piekarski, Ph.D. Alkyl Halides React with Nucleophiles and Bases Alkyl halides are polarized at the carbon- halide
More information10. Alkyl Halides. What Is an Alkyl Halide. An organic compound containing at least one carbonhalogen
10. Alkyl Halides What Is an Alkyl Halide An organic compound containing at least one carbonhalogen bond (C-X) X (F, Cl, Br, I) replaces H Can contain many C-X bonds Properties and some uses Fire-resistant
More informationDepartment of Chemistry SUNY/Oneonta. Chem Organic Chemistry I
Department of Chemistry SUNY/Oneonta Chem 221 - Organic Chemistry I Examination #4 - ANSWERS - December 11, 2000 Answer to question #32 corrected 12/13/00, 8:30pm. INSTRUCTIONS This examination is in multiple
More information