CHEM Lecture 7

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "CHEM Lecture 7"

Transcription

1 CEM 494 Special Topics in Chemistry Illinois at Chicago CEM Lecture 7 Prof. Duncan Wardrop ctober 22, 2012

2 CEM 494 Special Topics in Chemistry Illinois at Chicago Preparation of Alkenes Elimination Chapter 19

3 Dehydration can be Coupled with ther Chemical Transformation N Cl F N Cl F N Cl N N N Loratidine (Claritin ) Two-step, one-pot transformation involves a Friedel-Crafts reaction (see, Chapter 12) and dehydration of the resulting 3 alcohol CEM 494, Spring 2010 Slide 3

4 Rate of Alcohol Dehydration Mirrors Ease of Carbocation Formation rate of dehydration = 3º > 2º > 1º alcohol tertiary alcohol (3º) tertiary cation (3º) secondary alcohol (2º) Reactivity Stability secondary cation (2 ) primary alcohol (1º) primary cation (1 ) CEM 494, Spring 2010 Slide 4

5 Self Test Question Predict the product for the following reaction scheme. 2 S ºC? A. B. - β + β β - 2 β β C. D. β β β β E. no reaction CEM 494, Fall 2012 Slide 5

6 Predict the product for the following reaction scheme. Self Test Question 2 S ºC? A. B. - β + or - β β β β β β β C. D. β E. no reaction CEM 494, Fall 2012 Slide 6

7 CEM 494 Special Topics in Chemistry Illinois at Chicago Regioselectivity & Stereoselectivity of Dehydration Chapter 19

8 Self Test Question What is the product(s) of the following reaction? A. 2 S 4 80 ºC? B. C. D. E. 2 S CEM 494, Fall 2012 Slide 8

9 Types of Selectivity in rganic Chemistry There are three forms of selectivity to consider.... Chemoselectivity: which functional group will react Regioselectivity: where it will react Stereoselectivity: how it will react with regards to stereochemical outcome... for each transformation, always question which of these are factors are at play. CEM 494, Spring 2010 Slide 9

10 Regioselectivity of Elimination Regioselectivity: Where Will It React? Preferential reaction at one site of a single functional group over other sites that could undergo the same reaction CEM 232 Definition, S 4 80 ºC C C 3 C 3 10% (identical) 90% CEM 494, Spring 2010 Slide 10

11 Regioselectivity of Elimination Regioselectivity: Where Will It React? Preferential reaction at one site of a single functional group over other sites that could undergo the same reaction CEM 232 Definition, 2009 C 3 3 P C C 3 heat 84% 16% β β C3 β 2 different leaving group/ β relationships CEM 494, Spring 2010 Slide 11

12 Greek Lettering & Elimination Reactions Nomenclature The α-carbon is the one to which the leaving group is initially bonded, and the carbon chain from this may be labelled β (beta), γ (gamma), δ (delta) etc, following Greek alphabet. Use primed letters for chains branching at α-carbon δ 3 C γ 2 C Cl C 3 C C 2 β α 2 β' γ' CEM 494, Spring 2010 Slide 12

13 Regioselectivity of Elimination Zaitsev Rule Na + - S 2 s on this β carbon C C 3 3 C KS 4 3 C 3 hydrosulfate β α heat β C 3 β C 3 3 s on this β carbon 1 s on this β carbon C 3 + C 3 C % 13% 0% Zaitsev Rule When elimination can occur in more than one direction, the major alkene is the one formed by loss of a atom from the β carbon having the fewest hydrogens CEM 494, Spring 2010 Slide 13

14 Considering Stereo & Regioselectivity Combine Zaitsev s Rule and observations about stereoselectivity to predict the major products of dehydration (elimination) 2 S 4 80 ºC major product trisubstituted trisubstituted disubstituted disubstituted most stable alkenes have largest groups on each carbon trans to each other CEM 494, Spring 2010 Slide 14

15 Self Test Question What is the major product expected for the reaction scheme below? A. B. 2 S 4 80 ºC? C. D. E. CEM 494, Fall 2012 Slide 15

16 CEM 494 Special Topics in Chemistry Illinois at Chicago E1 & E2 chanisms of Alcohol Dehydration Chapter 19

17 rganic chanisms (S N 1) Cl fast & reversible alkyloxonium ion Cl slow Cl fast Cl carbocation (t-butyl cation) 2 t-butyl chloride CEM 494, Spring 2010 Slide 17

18 Remember Curved Arrow Notation? curved arrows show the movement of electrons; never atoms electrons atoms 3 C N C 3 resonance: electrons in a covalent bond moving out to an atom C bond making: lone pair of electrons forming a new bond to another atom 3 C N C 3 C 3 resonance: lone pair of electrons moving in between two atoms to form a new covalent bond 3 C 3 C + bond breaking: electrons in a bond leaving to most electronegative atom CEM 494, Spring 2010 Slide 18

19 chanism of Dehydration (E1) Step ne Proton Transfer (Protonation) S pka = -3.0 fast & reversible alkyloxonium ion S CEM 494, Spring 2010 Slide 19

20 Step Two Dissociation chanism of Dehydration (E1) slow 2 carbocation (t-butyl cation) CEM 494, Spring 2010 Slide 20

21 chanism of Dehydration (E1) Step Three Carbocation Capture β-deprotonation! C 2 S fast S carbocation (t-butyl cation) alkene (2-methylpropene) sulfuric acid (regenerated) S alkyl hydrogen sulfate (product of S N 1) CEM 494, Spring 2010 Slide 21

22 ughes-ingold Nomenclature slow carbocation (t-butyl cation) 2 E1 elimination unimolecular overall reaction = β-elimination rate determining step (RDS) involves on species = unimolecular rate = k[alkyl oxonium ion] = first order CEM 494, Spring 2010 Slide 22

23 Each Step of E1 chanism is Reversible S fast & reversible S slow & reversible C 2 S fast & reversible 2 If all steps in E1 are reversible, what drives the reaction forward? CEM 494, Spring 2010 Slide 23

24 Alkenes Isolated from Dehydration Reactions by Distillation 2 S methyl-2-pentanol bp = 132 ºC 2-methyl-1-pentene bp = 62 ºC 2-methyl-2-pentene bp = 67 ºC trans-4-methyl- 2-pentene bp = 59 ºC cis-4-methyl- 2-pentene bp = 58 ºC 4-methyl-1-pentene bp = 54 ºC alkenes have much lower boiling points than alcohols alcohols have higher boiling points (b.p.) because of larger van der Waals forces, including strong hydrogen-bonding by removing alkenes through distillation (boiling), equilibrium is shifted toward products (LeChatlier Principle) until no more reactants remain CEM 494, Spring 2010 Slide 24

25 Why Can t ydrogen alides Be Used for Elimination Reactions? slow & reversible Cl C 2 fast & reversible fast & reversible Cl Cl N u c l e o p h i l i c a d d i t i o n o f chloride (Cl ) to a carbocation is not reversible Cl fast & irreversible nucleophilic addition Cl alkyl chloride (product of S N 1) CEM 494, Spring 2010 Slide

26 Reactivity Explained R 2 R 1 = C R 2 R 3 R 2 = C R 3 = 2º Carbocation R 2 R 1 = C R 1 R 3 R 2 = C R 3 = C 3º Carbocation R 3 R 2 R R 3 R 2 R º carbocations are more stable than 2º = 3º lower in energy smaller activation energy leading to 3º carbocation results in faster reaction CEM 494, Spring 2010 Slide 26

27 Bimolecular Substitution - S N 2 chanism (from Lecture 8) 3 C Br fast 3 C Br 3 C slow (rate-determining) Step 1 Protonation Step 2 Nucleophilic Attack δ- Br C 3 C δ+ 3 C + Br C- bond breaks at the same time the nucleophile (Br) forms the C-X bond RDS is nucleophilic attack; bimolecular, therefore Ingold notation = S N 2 fewer steps does not mean faster reaction CEM 494, Spring 2010 Slide 27

28 Dehydration of Primary Alcohols Proceeds via E2 chanism 3 C S fast & reversible 3 C 3 C C 1 Cation S Step 1 Protonation Step 2 β-deprotonation (elimination) S β 2 C slow C- bond breaks at the same time the nucleophile (Br) forms the C-X bond RDS is nucleophilic attack; bimolecular, therefore Ingold notation = S N 2 fewer steps does not mean faster reaction CEM 494, Spring 2010 Slide 28

29 CEM 494 Special Topics in Chemistry Illinois at Chicago Regioselectivity & Stereoselectivity of Dehydration

30 Self Test Question What is the product(s) of the following reaction? A. 2 S 4 80 ºC? B. C. D. E. 2 S CEM 494, Fall 2012 Slide 30

31 Types of Selectivity in rganic Chemistry There are three forms of selectivity to consider.... Chemoselectivity: which functional group will react Regioselectivity: where it will react Stereoselectivity: how it will react with regards to stereochemical outcome... for each transformation, always question which of these are factors are at play. CEM 494, Spring 2010 Slide 31

32 Regioselectivity of Elimination Regioselectivity: Where Will It React? Preferential reaction at one site of a single functional group over other sites that could undergo the same reaction CEM 232 Definition, S 4 80 ºC C C 3 C 3 10% (identical) 90% CEM 494, Spring 2010 Slide 32

33 Regioselectivity of Elimination Regioselectivity: Where Will It React? Preferential reaction at one site of a single functional group over other sites that could undergo the same reaction CEM 232 Definition, 2009 C 3 3 P C C 3 heat 84% 16% β β C3 β 2 different leaving group/ β relationships CEM 494, Spring 2010 Slide 33

34 Greek Lettering & Elimination Reactions Nomenclature The α-carbon is the one to which the leaving group is initially bonded, and the carbon chain from this may be labelled β (beta), γ (gamma), δ (delta) etc, following Greek alphabet. Use primed letters for chains branching at α-carbon δ 3 C γ 2 C Cl C 3 C C 2 β α 2 β' γ' CEM 494, Spring 2010 Slide 34

35 Regioselectivity of Elimination Zaitsev Rule Na + - S 2 s on this β carbon C C 3 3 C KS 4 3 C 3 hydrosulfate β α heat β C 3 β C 3 3 s on this β carbon 1 s on this β carbon C 3 + C 3 C % 13% 0% Zaitsev Rule When elimination can occur in more than one direction, the major alkene is the one formed by loss of a atom from the β carbon having the fewest hydrogens CEM 494, Spring 2010 Slide 35

36 Considering Stereo & Regioselectivity Combine Zaitsev s Rule and observations about stereoselectivity to predict the major products of dehydration (elimination) 2 S 4 80 ºC major product trisubstituted trisubstituted disubstituted disubstituted most stable alkenes have largest groups on each carbon trans to each other CEM 494, Spring 2010 Slide 36

37 Self Test Question What is the major product expected for the reaction scheme below? A. B. 2 S 4 80 ºC? C. D. E. CEM 494, Fall 2012 Slide 37

38 CEM 494 Special Topics in Chemistry Illinois at Chicago E1 & E2 chanisms of Alcohol Dehydration Section: 5.12

39 rganic chanisms (S N 1) Cl fast & reversible alkyloxonium ion Cl slow Cl fast Cl carbocation (t-butyl cation) 2 t-butyl chloride CEM 494, Spring 2010 Slide 39

40 Remember Curved Arrow Notation? curved arrows show the movement of electrons; never atoms electrons atoms 3 C N C 3 resonance: electrons in a covalent bond moving out to an atom C bond making: lone pair of electrons forming a new bond to another atom 3 C N C 3 C 3 resonance: lone pair of electrons moving in between two atoms to form a new covalent bond 3 C 3 C + bond breaking: electrons in a bond leaving to most electronegative atom CEM 494, Spring 2010 Slide 40

41 chanism of Dehydration (E1) Step ne Proton Transfer (Protonation) S pka = -3.0 fast & reversible alkyloxonium ion S CEM 494, Spring 2010 Slide 41

42 Step Two Dissociation chanism of Dehydration (E1) slow 2 carbocation (t-butyl cation) CEM 494, Spring 2010 Slide 42

43 chanism of Dehydration (E1) Step Three Carbocation Capture β-deprotonation! C 2 S fast S carbocation (t-butyl cation) alkene (2-methylpropene) sulfuric acid (regenerated) S alkyl hydrogen sulfate (product of S N 1) CEM 494, Spring 2010 Slide 43

44 ughes-ingold Nomenclature slow carbocation (t-butyl cation) 2 E1 elimination unimolecular overall reaction = β-elimination rate determining step (RDS) involves on species = unimolecular rate = k[alkyl oxonium ion] = first order CEM 494, Spring 2010 Slide 44

45 Each Step of E1 chanism is Reversible S fast & reversible S slow & reversible C 2 S fast & reversible 2 If all steps in E1 are reversible, what drives the reaction forward? CEM 494, Spring 2010 Slide 45

46 Alkenes Isolated from Dehydration Reactions by Distillation 2 S methyl-2-pentanol bp = 132 ºC 2-methyl-1-pentene bp = 62 ºC 2-methyl-2-pentene bp = 67 ºC trans-4-methyl- 2-pentene bp = 59 ºC cis-4-methyl- 2-pentene bp = 58 ºC 4-methyl-1-pentene bp = 54 ºC alkenes have much lower boiling points than alcohols alcohols have higher boiling points (b.p.) because of larger van der Waals forces, including strong hydrogen-bonding by removing alkenes through distillation (boiling), equilibrium is shifted toward products (LeChatlier Principle) until no more reactants remain CEM 494, Spring 2010 Slide 46

47 Why Can t ydrogen alides Be Used for Elimination Reactions? slow & reversible Cl C 2 fast & reversible fast & reversible Cl Cl N u c l e o p h i l i c a d d i t i o n o f chloride (Cl ) to a carbocation is not reversible Cl fast & irreversible nucleophilic addition Cl alkyl chloride (product of S N 1) CEM 494, Spring 2010 Slide

48 Reactivity Explained R 2 R 1 = C R 2 R 3 R 2 = C R 3 = 2º Carbocation R 2 R 1 = C R 1 R 3 R 2 = C R 3 = C 3º Carbocation R 3 R 2 R R 3 R 2 R º carbocations are more stable than 2º = 3º lower in energy smaller activation energy leading to 3º carbocation results in faster reaction CEM 494, Spring 2010 Slide 48

49 Bimolecular Substitution - S N 2 chanism (from Lecture 8) 3 C Br fast 3 C Br 3 C slow (rate-determining) Step 1 Protonation Step 2 Nucleophilic Attack δ- Br C 3 C δ+ 3 C + Br C- bond breaks at the same time the nucleophile (Br) forms the C-X bond RDS is nucleophilic attack; bimolecular, therefore Ingold notation = S N 2 fewer steps does not mean faster reaction CEM 494, Spring 2010 Slide 49

50 Dehydration of Primary Alcohols Proceeds via E2 chanism 3 C S fast & reversible 3 C 3 C C 1 Cation S Step 1 Protonation Step 2 β-deprotonation (elimination) S β 2 C slow C- bond breaks at the same time the nucleophile (Br) forms the C-X bond RDS is nucleophilic attack; bimolecular, therefore Ingold notation = S N 2 fewer steps does not mean faster reaction CEM 494, Spring 2010 Slide 50

51 CEM 494 Special Topics in Chemistry Illinois at Chicago Addition Reactions of Alkenes

52 Addition Reactions of Alkenes C C + X Y addition X C C Y C C + hydrogenation C C C C + X hydrogen halide addition C C X C C + Br free radical bromine addition C C Br C C + S sulfuric acid addition C C S 3 C C + hydration C C CEM 494, Spring 2010 Slide 52

53 ydrogenation Pd/C, C3C2 exothermic reaction (- º), but high E act - catalyst required catalysts are heterogeneous transition metals (Pd, R solvent is typically an alcohol (e.g. ethanol, C 3 C2) metals are insoluble (heterogeneous mixture) heat of hydrogenation = - º CEM 494, Spring 2010 Slide 53

54 eat of ydrogenation (- º) CEM 494, Spring 2010 Slide 54

55 eat of ydrogenation (- º) Since only the double bond is undergoing the reaction, heat of hydrogenation is independent of the number of carbon atoms in the molecule Alkene - º (kj/mol) example ethylene 136 monosubstituted 126 cis-disubstituted 119 terminally disubstituted 117 trisubstituted 112 tetrasubstituted 110 CEM 494, Spring 2010 Slide 55

56 General chanism for eterogenious ydrogenation σ d reductive elimination catalyst surface M II catalyst surface M 0 oxidative addition catalyst surface M II reaction takes places at the surface of the catalyst (many metal atoms combined) insertion coordination catalyst surface M II CEM 494, Spring 2010 Slide 56

57 Step 1: xidative Addition d σ hydrogen (2) is added to metal metal is oxidized from M 0 to M II catalyst surface M 0 oxidative addition catalyst surface M II Pd 0 Pd II CEM 494, Spring 2010 Slide 57

58 Step 2: Coordination metal is a Lewis acid (electron acceptor) π-bond is a lewis base (electron donor) coordination = Lewis acid/base complex Pd II Pd II catalyst surface M II coordination catalyst surface M II CEM 494, Spring 2010 Slide 58

59 Step 3: Insertion two carbon atoms inserted between Pd- formation of a weak metal-carbon σ-bond formation of a strong C- σ-bond break a weak metal- σ-bond Pd II Pd II catalyst surface M II insertion catalyst surface M II CEM 494, Spring 2010 Slide 59

60 Step 4: Reductive Elimination d σ catalyst surface M 0 reductive elimination catalyst surface M II metal is reduced from M II to M 0 last σ C- -bond is formed from the same face of alkene as previous metal is a catalyst; it is regenerated Pd II CEM 494, Spring 2010 Slide 60

61 Complete chanism reductive elimination Pd 0 oxidative addition Pd II Pd II insertion Pd II coordination CEM 494, Spring 2010 Slide 61

62 Syn Addition of ydrogen as a consequence of mechanism, both hydrogens are added to the same face of the π-bond: syn addition no anti-addition products are formed (addition of hydrogen to opposite faces) CEM 494, Spring 2010 Slide 62

63 ydrogenation is Stereoselective This methyl group sterically hinders hydrogen from approaching the π-bond from the top face both products are arise from syn additions of hydrogen to alkene stereoselective: preference for one stereoisomer when two or more are possible CEM 494, Spring 2010 Slide 63

64 Example of Syn Addition C 3 C 3 C 8 12 C 3 C 3 C 8 12 C 3 C 3 C Diatomic hydrogen and alkene are present in solution phase. No reaction occurs. 2. ydrogen absorbed on to catalyst surface. - bond cleaved. 3. π System of alkene coordinates catalyst surface. C 3 C 3 C 8 12 C 3 C 3 C 8 12 C 3 C 3 C ne hydrogen atom is transferred to alkene, forming C-catalyst bond. 5. Second hydrogen atom is transferred, breaking substrate-catalyst bond. Alkane diffuses away from catalyst. 6. Steps 1-5 are repeated. CEM 494, Spring 2010 Slide 64

65 Self Test Question What is the major product of the following hydrogenation reaction? D 2, Pd/C A. D C 3 C 2 B. D D M II catalyst surface C. D catalyst surface M II D D. D CEM 494, Fall 2012 Slide 65

66 Addition of Electrophiles to Alkene C C + hydrogenation C C C C + X hydrogen halide addition C C X C C + Br free radical bromine addition C C Br C C + S sulfuric acid addition C C S 3 C C + hydration C C CEM 494, Spring 2010 Slide 66

67 Electrophilic Addition of X + δ + δ C C X hydrogen halide addition C C X nucleophile electrophile CEM 494, Spring 2010 Slide 67

68 Reaction Conditions Br Br CCl 3, -30 ºC hydrogen halide: X common solvents: chloroform (CCl 3 ),dichloromethane (C 2 Cl 2 ), pentane, acetic acid generally performed at low temperature (below 0 C) generally a fast reaction CEM 494, Spring 2010 Slide 68

69 Electrophilic Addition (Ad E ) chanism Br Protonation (slow) Br Br Cation Capture (fast) electrophilic addition: AdE RDS = protonation of carbon rate = k[alkene][hydrogen halide] unlike oxygen and nitrogen, protonation of carbon is slow proceeds through carbocation intermediate CEM 494, Spring 2010 Slide 69

70 X Addition is Regioselective Regioselectivity Preferential reaction at one site of a single functional group over other sites that could undergo the same reaction CEM 232 Definition, 2010 R X R R rather than X X R R X R R rather than R R X X R R R X R R rather than R R R X R X CEM 494, Spring 2010 Slide 70

71 Markovnikov s Rule 3º C 3 2º Br 3 C Br C 2 Cl 2-40 ºC addition of X to an unsymmetrically substituted alkene proceeds so that hydrogen () adds to the least substituted carbon and the halide (X) adds to the most substituted carbon atom 71 CEM 494, Spring 2010 Slide

72 Self Test Question Predict the product when 2,4-dimethyl-2-pentene is treated with Cl? A. 3-chloro-2,4-dimethylpentane Cl Cl B. 2-chloroohexane C. 2,3-dichloro-2,4-dimethylpentane D. 2-chloro-2,4-dimethylpentane E. 1-chloro-2,4-dimethylpentane CEM 494, Fall 2012 Slide 72

73 chanistic Basis for Markovnikov s Rule X X X 3º carbocation 3º alkyl halide X X + 2º carbocation X 2º alkyl halide curved arrows do not indicate which carbon is protonated fastest protonation leads to more stable (more substituted) carbocation more substituted carbocation = more substituted alkyl halide CEM 494, Spring 2010 Slide 73

74 chanistic Basis for Markovnikov s Rule ammond Postulate: transition state structure resembles closest energy intermediate transition state resembles carbocation for endothermic RDS (late transition state) what stabilizes carbocation also stabilizes transition state lowest energy transition state leads to more substituted carbocation CEM 494, Spring 2010 Slide 74

Lecture 11 Organic Chemistry 1

Lecture 11 Organic Chemistry 1 EM 232 rganic hemistry I at hicago Lecture 11 rganic hemistry 1 Professor Duncan Wardrop February 16, 2010 1 Self Test Question What is the product(s) of the following reaction? 3 K( 3 ) 3 A 3 ( 3 ) 3

More information

Structure and Preparation of Alkenes: Elimination Reactions

Structure 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 information

Lecture 20 Organic Chemistry 1

Lecture 20 Organic Chemistry 1 CEM 232 rganic Chemistry I at Chicago Lecture 20 rganic Chemistry 1 Professor Duncan Wardrop March 18, 2010 1 Self-Test Question Capnellene (4) is a marine natural product that was isolated from coral

More information

Chapter 7 Alkenes; Elimination Reactions

Chapter 7 Alkenes; Elimination Reactions hapter 7 Alkenes; Elimination Reactions Alkenes Alkenes contain a carbon-carbon double bond. They are named as derivatives of alkanes with the suffix -ane changed to -ene. The parent alkane is the longest

More information

Elimination Reactions Heating an alkyl halide with a strong base causes elimination of a. molecule of HX

Elimination 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 information

OChem 1 Mechanism Flashcards. Dr. Peter Norris, 2018

OChem 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 information

CHEM Lecture 5

CHEM Lecture 5 CEM 494 Special Topics in Chemistry Illinois at Chicago CEM 494 - Lecture 5 Prof. Duncan Wardrop ctober 8, 2012 CEM 494 Special Topics in Chemistry Illinois at Chicago Chapter 15 Alcohols and Alkyl alides

More information

Basic Organic Chemistry Course code : CHEM (Pre-requisites : CHEM 11122)

Basic 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 information

CHEM Lecture 6

CHEM Lecture 6 EM 494 Special Topics in hemistry Illinois at hicago EM 494 - Lecture 6 Prof. Duncan Wardrop October 15, 2012 Midterm Papers Factors that ontrol ydrocarbon Acidity Factors that ontrol ydrocarbon onformation

More information

CHE1502. Tutorial letter 201/1/2016. General Chemistry 1B. Semester 1. Department of Chemistry CHE1502/201/1/2016

CHE1502. 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 information

OChem 1 Mechanism Flashcards. Dr. Peter Norris, 2015

OChem 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 information

Chapter 9. Nucleophilic Substitution and ß-Elimination

Chapter 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 information

Lecture 22 Organic Chemistry 1

Lecture 22 Organic Chemistry 1 CEM 232 rganic Chemistry I at Chicago Lecture 22 rganic Chemistry 1 Professor Duncan Wardrop April 1, 2010 1 Self Test Question Which starting material could not be used to prepare the tribromide below?

More information

Chapter 10 Lecture Outline

Chapter 10 Lecture Outline Organic Chemistry, Fifth Edition Janice Gorzynski Smith University of Hawai i Chapter 10 Lecture Outline Modified by Dr. Juliet Hahn Copyright 2017 McGraw-Hill Education. All rights reserved. No reproduction

More information

Classes of Alkenes. Alkenes and Alkynes. Saturated compounds (alkanes): Have the maximum number of hydrogen atoms attached to each carbon atom.

Classes 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 information

1.13 Acid-Base Reactions: Lone-Pair Donors & Acceptors

1.13 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 information

Name: Chapter 3: The Nature Of Organic Reactions: Alkenes

Name: Chapter 3: The Nature Of Organic Reactions: Alkenes Name: Chapter 3: The Nature Of Organic Reactions: Alkenes 1 Vocabulary cis-trans isomerism: E,Z designation: Addition: Elimination: Substitution: Rearrangement: Homolytic: Heterolytic Homogenic: Heterogenic:

More information

Lecture 18 Organic Chemistry 1

Lecture 18 Organic Chemistry 1 CEM 232 rganic Chemistry I at Chicago Lecture 18 rganic Chemistry 1 Professor Duncan Wardrop March 9, 2010 1 Nucleophilicity nucleophilicity: measures the strength of the nucleophile ; more nucleophilic

More information

Chapter 5. Reactions of Alkenes and Alkynes

Chapter 5. Reactions of Alkenes and Alkynes Chapter 5. Reactions of Alkenes and Alkynes Learning objectives: 1. Identify the followings from a reaction coordinate diagram when applicable: endothermic or exothermic reactions, activation energy, heat

More information

Homework - Review of Chem 2310

Homework - Review of Chem 2310 omework - Review of Chem 2310 Chapter 1 - Atoms and Molecules Name 1. What is organic chemistry? 2. Why is there an entire one year course devoted to the study of organic compounds? 3. Give 4 examples

More information

CHEM 263 Oct 25, stronger base stronger acid weaker acid weaker base

CHEM 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 information

Acid-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

Acid-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 information

C 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 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 information

Chapter 10 Radical Reactions"

Chapter 10 Radical Reactions Chapter 10 Radical Reactions Radicals are intermediates with an unpaired electron H. Cl. Hydrogen radical t Often called free radicals What are radicals? Chlorine radical t Formed by homolytic bond cleavage

More information

Chapter 3. Alkenes And Alkynes

Chapter 3. Alkenes And Alkynes Chapter 3 Alkenes And Alkynes Alkenes ydrocarbons containing double bonds C C double bond the functional group center of reactivity Molecular Formula of Alkene Acyclic alkene: C n 2n Cyclic alkene: C n

More information

CHAPTER 7. Further Reactions of Haloalkanes: Unimolecular Substitution and Pathways of Elimination

CHAPTER 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

Chapter 8 Alkenes and Alkynes II: Addition Reactions

Chapter 8 Alkenes and Alkynes II: Addition Reactions Chapter 8 Alkenes and Alkynes II: Addition Reactions Introduction: Additions to Alkenes Generally the reaction is exothermic because one π and one σ bond are converted to two σ bonds The π electrons of

More information

Physical Properties: Structure:

Physical 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 information

Chapter 8 Addition Reactions to Alkenes

Chapter 8 Addition Reactions to Alkenes . 8 hapter 8 Addition eactions to Alkenes In this chapter will we study the addition reactions of alkenes. We will see that the π electrons of the double bond are loosely held and that their maximum electron

More information

Chapter 8 Alkenes and Alkynes II: Addition Reactions "

Chapter 8 Alkenes and Alkynes II: Addition Reactions Chapter 8 Alkenes and Alkynes II: Addition Reactions Additions to Alkenes Generally the reaction is exothermic because one π and one σ bond are converted to two σ bonds Alkenes are electron rich The π

More information

REACTION AND SYNTHESIS REVIEW

REACTION 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 information

B. (2 pts) The regiochemistry of alcohol dehydration is determined by the: a. Zaitsev rule; b. Hammond postulate;

B. (2 pts) The regiochemistry of alcohol dehydration is determined by the: a. Zaitsev rule; b. Hammond postulate; CEMISTRY 313-01 MIDTERM # answer key ctober 1, 008 Statistics: Average: 73 pts (73%); ighest: 98 pts (98%); Lowest: 3 pts (3%) Number of students performing at or above average: 36 (58%) Number of students

More information

CHE1502. Tutorial letter 203/1/2016. General Chemistry 1B. Semester 1. Department of Chemistry

CHE1502. 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 information

Preparation of alkenes

Preparation 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 information

C C. sp 2. π M.O. atomic. orbitals. carbon 1. σ M.O. molecular. orbitals. H C C rotate D. D H zero overlap of p orbitals: π bond broken!

C C. sp 2. π M.O. atomic. orbitals. carbon 1. σ M.O. molecular. orbitals. H C C rotate D. D H zero overlap of p orbitals: π bond broken! Alkenes Electrophilic Addition 1 Alkene Structures chemistry of double bond σ BDE ~ 80 kcal/mol π = BDE ~ 65 kcal/mol The p-bond is weaker than the sigma-bond The, electrons in the p-bond are higher in

More information

Organic Chemistry Review: Topic 10 & Topic 20

Organic Chemistry Review: Topic 10 & Topic 20 Organic Structure Alkanes C C σ bond Mechanism Substitution (Incoming atom or group will displace an existing atom or group in a molecule) Examples Occurs with exposure to ultraviolet light or sunlight,

More information

Hydrogen iodide is a strong acid and will drive the reverse reaction, meaning the forward reaction will not occur.

Hydrogen iodide is a strong acid and will drive the reverse reaction, meaning the forward reaction will not occur. EM 261 Oct 18, 2018 Photosynthesis and Related Reactions O 2 2 O 6 12 O 6 2 O N 3, S, Fe, u, o, other Natural Products D-Glucose R O R OR Ionic substitution S N 1 & R X X 2 hv Petroleum/ Alkanes R N 2

More information

(Neither an oxidation or reduction: Addition or loss of H +, H 2 O, HX).

(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 information

ORGANIC CHEMISTRY- 1

ORGANIC CHEMISTRY- 1 ORGANIC CEMISTRY- 1 ALKENES Alkenes are also called Olefins (C n 2n ) unsaturated hydrocarbons. Alkenes occur abundantly in nature. Ethylene ( 2 C=C 2 ) is a plant hormone that induces ripening in fruit.

More information

Chemistry 110. Bettelheim, Brown, Campbell & Farrell. Introduction to General, Organic and Biochemistry Chapter 12 Alkenes & Alkynes.

Chemistry 110. Bettelheim, Brown, Campbell & Farrell. Introduction to General, Organic and Biochemistry Chapter 12 Alkenes & Alkynes. Chemistry 110 Bettelheim, Brown, Campbell & Farrell Ninth Edition Introduction to General, Organic and Biochemistry Chapter 12 Alkenes & Alkynes Chapter 12 Alkenes are hydrocarbons which have one or more

More information

Chemistry 110 Bettelheim, Brown, Campbell & Farrell Ninth Edition Introduction to General, Organic and Biochemistry Chapter 12 Alkenes & Alkynes

Chemistry 110 Bettelheim, Brown, Campbell & Farrell Ninth Edition Introduction to General, Organic and Biochemistry Chapter 12 Alkenes & Alkynes Chemistry 110 Bettelheim, Brown, Campbell & Farrell Ninth Edition Introduction to General, Organic and Biochemistry Chapter 12 Alkenes & Alkynes Chapter 12 Alkenes are hydrocarbons which have one or more

More information

Chapter 8 Reactions of Alkenes

Chapter 8 Reactions of Alkenes Chapter 8 Reactions of Alkenes Electrophilic Additions o Regio vs stereoselectivity Regio where do the pieces add? Markovnikov s rule hydrogen will go to the side of the double bond with most hydrogens.

More information

8. What is the slow, rate-determining step, in the acidcatalyzed dehydration of 2-methyl-2-propanol?

8. What is the slow, rate-determining step, in the acidcatalyzed dehydration of 2-methyl-2-propanol? CHEMISTRY 313-03 MIDTERM # 2 answer key October 25, 2011 Statistics: Average: 68 pts (68%); Highest: 100 pts (100%); Lowest: 30 pts (30%) Number of students performing at or above average: 56 (54%) Number

More information

Chapter 8 Alkyl Halides and Elimination Reactions

Chapter 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 information

Alkenes. Dr. Munther A. M-Ali For 1 st Stage Setudents

Alkenes. Dr. Munther A. M-Ali For 1 st Stage Setudents Alkenes Dr. Munther A. M-Ali For 1 st Stage Setudents Alkenes Family of hydrocarbons, the alkenes, which contain less hydrogen, carbon for carbon, than the alkanes Structure of ethylene, The carbon-carbon

More information

Chapter 8: Chemistry of Alkynes (C n H 2n-2 )

Chapter 8: Chemistry of Alkynes (C n H 2n-2 ) hapter 8: hemistry of Alkynes ( n 2n-2 ) Bonding & hybridization Both are sp-hybridized Bond angles = 180 o 1 σ + 2 π bonds Linear around lassification R R R' σ bond energy: 88 kcal/mol π bond energy:

More information

Alkenes. Alkenes-hydrocarbons with a carbon-carbon double bond. Alkenes have the formula C n H 2n. Nomenclature

Alkenes. Alkenes-hydrocarbons with a carbon-carbon double bond. Alkenes have the formula C n H 2n. Nomenclature Alkenes Alkenes-hydrocarbons with a carbon-carbon double bond. Alkenes have the formula n 2n. Nomenclature Alkenes are named in the same manner as alkanes with the following adjustments. 1. Find the longest

More information

1. Radical Substitution on Alkanes. 2. Radical Substitution with Alkenes. 3. Electrophilic Addition

1. 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 information

Lecture Topics: I. Electrophilic Aromatic Substitution (EAS)

Lecture 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 information

Chapter 8 Alkenes and Alkynes II: Addition Reactions. Alkenes are electron rich. Additions to Alkenes

Chapter 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 information

Lecture 21 Organic Chemistry 1

Lecture 21 Organic Chemistry 1 CEM 232 Organic Chemistry I at Chicago Lecture 21 Organic Chemistry 1 Professor Duncan Wardrop March 30, 2010 1 Self Test Question Ethanolysis of alkyl halide 1 gives ether 2 as one product; however, several

More information

Dehydrohalogenation of Alkyl Halides E2 and E1 Reactions in Detail

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 information

75. A This is a Markovnikov addition reaction. In these reactions, the pielectrons in the alkene act as a nucleophile. The strongest electrophile will

75. 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 information

4. Alkenes are nucleophiles and like to attack electrophiles, like protons, with positive charges:

4. Alkenes are nucleophiles and like to attack electrophiles, like protons, with positive charges: Mechanism Steps: Answer Key 1. Alcohols are nucleophilic and like to grab protons,, to form water molecules: 2. 3. 4. Alkenes are nucleophiles and like to attack electrophiles, like protons, with positive

More information

Organic Chemistry Lecture 2 - Hydrocarbons, Alcohols, Substitutions

Organic 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 information

Chapter 4. Reactions of alkenes. Addition reactions Carbocations Selectivity of reactions

Chapter 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 information

Chapter 8: Alkene Structure and Preparation via Elimination Reactions

Chapter 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 information

This reactivity makes alkenes an important class of organic compounds because they can be used to synthesize a wide variety of other compounds.

This reactivity makes alkenes an important class of organic compounds because they can be used to synthesize a wide variety of other compounds. This reactivity makes alkenes an important class of organic compounds because they can be used to synthesize a wide variety of other compounds. Mechanism for the addition of a hydrogen halide What happens

More information

7. Haloalkanes (text )

7. 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 information

Elimination Reactions. Chapter 6 1

Elimination 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 information

But in organic terms: Oxidation: loss of H 2 ; addition of O or O 2 ; addition of X 2 (halogens).

But 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 information

Chapter 5. Nucleophilic aliphatic substitution mechanism. by G.DEEPA

Chapter 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 information

Chapter 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 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 information

Chapter 04 Alcohols and Alkyl Halides part 01

Chapter 04 Alcohols and Alkyl Halides part 01 hapter 04 Alcohols and Alkyl alides part 01 EM 341: Spring 2012 Prof. Greg ook Functional Groups A functional group is a structural feature in a molecule that has characteristic reactivity. A functional

More information

REVIEW PROBLEMS Key. 1. Draw a complete orbital picture for the molecule shown below. Is this molecule chiral? Explain. H H.

REVIEW PROBLEMS Key. 1. Draw a complete orbital picture for the molecule shown below. Is this molecule chiral? Explain. H H. rganic hemistry II (E325) REVIEW PRBLEMS Key 1. Draw a complete orbital picture for the molecule shown below. Is this molecule chiral? Explain. 3 3 sp3 orbital p orbital sp2 orbital s orbital molecule

More information

Alkenes (Olefins) Chapters 7 & 8 Organic Chemistry, 8 th Edition John McMurry

Alkenes (Olefins) Chapters 7 & 8 Organic Chemistry, 8 th Edition John McMurry Alkenes (Olefins) Chapters 7 & 8 Organic Chemistry, 8 th Edition John McMurry 1 Structure and Bonding 2 Structure and Bonding Rotation around the C=C bond is restricted 90 rotation The p orbitals are orthogonal

More information

Glendale Community College Chemistry 105 Exam. 3 Lecture Notes Chapters 6 & 7

Glendale 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 information

An Overview of Organic Reactions. Reaction types: Classification by outcome Most reactions produce changes in the functional group of the reactants:

An Overview of Organic Reactions. Reaction types: Classification by outcome Most reactions produce changes in the functional group of the reactants: An Overview of Organic Reactions Reaction types: Classification by outcome Most reactions produce changes in the functional group of the reactants: 1. Addition (forward) Gain of atoms across a bond Example:

More information

CHEMISTRY MIDTERM # 2 October 27, The total number of points in this midterm is 100. The total exam time is 120 min (2 h). Good luck!

CHEMISTRY MIDTERM # 2 October 27, The total number of points in this midterm is 100. The total exam time is 120 min (2 h). Good luck! EMISTRY 313-01 MIDTERM # 2 ctober 27, 2005 Name... The total number of points in this midterm is 100. The total exam time is 120 min (2 h). Good luck! 1. (7 pts) Mark as true (T) or false (F) the following

More information

5. Reactions of Alkenes (text )

5. Reactions of Alkenes (text ) 2009, Department of hemistry, The University of Western Ontario 5.1 5. Reactions of Alkenes (text 5.1 5.5) A. Addition Reactions In hapter 4, we saw that π bonds have electron density on two sides of the

More information

MCAT Organic Chemistry Problem Drill 10: Aldehydes and Ketones

MCAT 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 information

Chapter 10 Free Radicals

Chapter 10 Free Radicals hapter 10 Free Radicals This is an example of a free radical reaction. A radical is a species that has a free unpaired electron. There are several examples of stable radicals, the most common of which

More information

Química Orgânica I. Organic Reactions

Química Orgânica I. Organic Reactions Química Orgânica I 2008/09 w3.ualg.pt\~abrigas QOI 0809 A6 1 Organic Reactions Addition two molecules combine Elimination one molecule splits Substitution parts from two molecules exchange Rearrangement

More information

Organic Halogen Compounds

Organic Halogen Compounds 8 Organic alogen ompounds APTER SUMMARY 8.1 Introduction Although organic halogen compounds are rarely found in nature, they do have a variety of commercial applications including use as insecticides,

More information

Lab Activity 9: Introduction to Organic Chemical Reactivity, Lab 5 Prelab, Reflux

Lab Activity 9: Introduction to Organic Chemical Reactivity, Lab 5 Prelab, Reflux Lab Activity 9: Introduction to Organic Chemical Reactivity, Lab 5 Prelab, Reflux Objectives 1. Identify structural features (pi bonds, bond polarity, lone pairs) of a compound 2. Determine whether a structural

More information

What are radicals? H. Cl. Chapter 10 Radical Reactions. Production of radicals. Reactions of radicals. Electronic structure of methyl radical

What are radicals? H. Cl. Chapter 10 Radical Reactions. Production of radicals. Reactions of radicals. Electronic structure of methyl radical What are radicals? Radicals are intermediates with an unpaired electron Chapter 10 Radical Reactions H. Cl. Hydrogen radical Chlorine radical Methyl radical Often called free radicals Formed by homolytic

More information

Chapter 8: Alkene Structure and Preparation via Elimination Reactions

Chapter 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 information

Chapter 7 - Alkenes and Alkynes I

Chapter 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 information

Some Arrow-Pushing Guidelines (Section 1.14) 1. Arrows follow electron movement.

Some Arrow-Pushing Guidelines (Section 1.14) 1. Arrows follow electron movement. Chem 350 Jasperse Ch. 1 Notes 1 Note: The headers and associated chapters don t actually jive with the textbook we are using this summer. But otherwise this highlights a lot of the chemistry from Organic

More information

CHAPTER 16 - CHEMISTRY OF BENZENE: ELECTROPHILIC AROMATIC SUBSTITUTION

CHAPTER 16 - CHEMISTRY OF BENZENE: ELECTROPHILIC AROMATIC SUBSTITUTION CAPTR 16 - CMISTRY F BNZN: LCTRPILIC ARMATIC SUBSTITUTIN As stated in the previous chapter, benzene and other aromatic rings do not undergo electrophilic addition reactions of the simple alkenes but rather

More information

COURSE OBJECTIVES / OUTCOMES / COMPETENCIES.

COURSE OBJECTIVES / OUTCOMES / COMPETENCIES. COURSE OBJECTIVES / OUTCOMES / COMPETENCIES. By the end of the course, students should be able to do the following: See Test1-4 Objectives/Competencies as listed in the syllabus and on the main course

More information

Chapter 7: Alkenes and Alkynes

Chapter 7: Alkenes and Alkynes Chapter 7: Alkenes and Alkynes ydrocarbons Containing Double and Triple Bonds Unsaturated Compounds (Less than Maximum Atoms) Alkenes also Referred to as Olefins Properties Similar to those of Corresponding

More information

REACTIONS OF HALOALKANES - SUBSTITUTION AND ELIMINATION

REACTIONS 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 information

1. What are the respective hybridizations of the atoms numbered 1 to 4 in this compound?

1. What are the respective hybridizations of the atoms numbered 1 to 4 in this compound? CEM 331: Chapter 1/2: Structures (Atoms, Molecules, Bonding) 1. What are the respective hybridizations of the atoms numbered 1 to 4 in this compound? N C 2 C N C 2 C N 1 2 3 4 1: three sigma bonds and

More information

212 LSW ALKYNES S04. Alkynes

212 LSW ALKYNES S04. Alkynes Alkynes Doubly unsaturated functional group Terminal alkynes, R-- 1) 2) 3) 4) Nomenclature: Functional group suffix = Disubstituted alkynes, R--R' Monosubstituted alkynes, R-- Stability: Substituted alkynes

More information

Topic 2 Alkenes and alkynes

Topic 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 information

Chapter 8 Alkenes and Alkynes II: Addition Reactions. Alkenes are electron rich. Additions to Alkenes

Chapter 8 Alkenes and Alkynes II: Addition Reactions. Alkenes are electron rich. Additions to Alkenes Additions to Alkenes hapter 8 Alkenes and Alkynes II: Addition eactions Generally the reaction is exothermic because one π and one σ bond are converted to two σ bonds Alkenes are electron rich The carbocation

More information

Chapter 8: Addition Reactions

Chapter 8: Addition Reactions Chapter 8: Addition Reactions Addition Reactions to Alkenes (Section 8.1) Markovnikov s Rule (Section 8.2) Stereochemistry of Ionic Addition to Alkenes (Section 8.3) 2 S 4 Additions to Alkenes (Section

More information

Alcohols, Ethers, & Epoxides

Alcohols, 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 information

1. Addition of HBr to alkenes

1. Addition of HBr to alkenes eactions of Alkenes I eading: Wade chapter 8, sections 8-1- 8-8 tudy Problems: 8-47, 8-48, 8-55, 8-66, 8-67, 8-70 Key Concepts and kills: Predict the products of additions to alkenes, including regiochemistry

More information

Understanding the basics. Mechanisms 5/24/11

Understanding the basics. Mechanisms 5/24/11 Understanding the basics Mechanisms Some Basic rgo I Reactions Mechanisms are the most mind-boggling part of organic chemistry. Students, generally speaking, have spent their time memorizing their way

More information

Lecture 9 Organic Chemistry 1

Lecture 9 Organic Chemistry 1 EM 232 Organic hemistry I at hicago Lecture 9 Organic hemistry 1 Prof. Duncan J. Wardrop 02/09/2010 1 Functional Group larification Although they can be viewed as ethers, epoxides are classified as distinct,

More information

Nuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320

Nuggets 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 information

Electrophilic Addition

Electrophilic Addition . Reactivity of = Electrons in pi bond are loosely held. Electrophiles are attracted to the pi electrons. arbocation intermediate forms. Nucleophile adds to the carbocation. Net result is addition to the

More information

Chapter 15: Conjugated Systems, Orbital Symmetry, and UV Spectroscopy

Chapter 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 information

Homework problems Chapters 6 and Give the curved-arrow formalism for the following reaction: CH 3 OH + H 2 C CH +

Homework 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 information

CHEMISTRY Topic #4: Electrophilic Addition Reactions of Alkenes and Alkynes Fall 2018 Dr. Susan Findlay

CHEMISTRY Topic #4: Electrophilic Addition Reactions of Alkenes and Alkynes Fall 2018 Dr. Susan Findlay EMISTRY 2600 Topic #4: Electrophilic Addition Reactions of Alkenes and Alkynes Fall 2018 Dr. Susan Findlay rganic Reactions (EM 2500 Review) Most reactions in organic chemistry fall into one (or more)

More information

HONORS ORGANIC CHEM. HAHS MRS. RICHARDS

HONORS ORGANIC CHEM. HAHS MRS. RICHARDS NRS RGANIC CEM. AS MRS. RICARDS RGANIC CEMISTRY: FINAL EXAM REVIEW List of Topics: While the exam will specifically focus on material from Quarter 2, an understanding of several important concepts from

More information

less stable intermediate

less stable intermediate 166 CAPTER 4 INTRODUCTION TO ALKENES. STRUCTURE AND REACTIVITY STANDARD FREE ENERGY higher-energy transition state less stable intermediate (C 3 ) 2 CC 2 Br _ (C 3 ) 2 C A C 2 + Br (C 3 ) 2 CC 2 L Br slower

More information

Organic Chemistry I Lesson Objectives, Lesson Problems, Course Outline Spring 2008

Organic Chemistry I Lesson Objectives, Lesson Problems, Course Outline Spring 2008 Organic Chemistry I Lesson Objectives, Lesson Problems, Course Outline Spring 2008 Lesson Date Assignment Lesson Objective Description Lesson Problems 4 14-Jan Chapter 1 Quiz Describe how bond polarity

More information