Dr. Dina akhotmah-232 1

Size: px
Start display at page:

Download "Dr. Dina akhotmah-232 1"

Transcription

1 Dr. Dina akhotmah-232 1

2 Chemistry of polyfunction 1. Types of carbon atom Dr. Dina akhotmah-232 2

3 Classification of multiple bonds of polyunsaturated compounds Dr. Dina akhotmah-232 3

4 Organic chemistry, solomons, 10 th edition, page 599 Many hydrocarbons are known that contain more than one double or triple bond: a) Hydrocarbons with two double bonds is called an alkadiene (or dienes) b) three double bonds is called an alkatriene (or trienes), and so on c) A hydrocarbon with two triple bonds is called an alkadiyne d) a hydrocarbon with a double and triple bond is called an alkenyne The following examples explain how specific compounds are named. Dr. Dina akhotmah-232 4

5 Allylic substitution and allyl radical Reference organic chemistry, solomons, chapter 13, page 585- when propene for example reacts with chlorine or bromine at low temperatures, an addition reaction of halogen to the double bond is take place However, when propene for example reacts with chlorine or bromine at very high temperatures or low concentration of the halogen, the reaction that occurs is a substitution Dr. Dina akhotmah-232 5

6 Dr. Dina akhotmah-232 6

7 Why allyl product is formed? Dr. Dina akhotmah-232 7

8 Dr. Dina akhotmah-232 8

9 Dr. Dina akhotmah-232 9

10 The resonance description of the allyl radical The allyl compound break either hemolytic producing free radical Heterolytic producing cation or anion All these product resonate witch explain its stability, high reactivity and the possibility to form two products. For an example: Why B is the major product? Think back to Zaitsev s rule the more substituted an alkene is, the more stable it is Dr. Dina akhotmah

11 H C C H C H 3 N B S, h e a t C C l 4 H H C A C H d i r e c t p r o d u c t C H 2 B r H C C H 2 C B r B a l l y l i c r e a r r a n g m e n t p r o d u c t Dr. Dina akhotmah

12 Dr. Dina akhotmah

13 Organic Chemistry, solomons, 10 th edition, page 602 Dr. Dina akhotmah

14 Conjugated alkadienes are thermodynamically more stable than isomeric isolated alkadienes, these stability can be seen in an analysis of the heat of hydrogenation. For an example, Dr. Dina akhotmah

15 Dr. Dina akhotmah

16 Electrophilic Attack on Conjugated Dienes 1,4 Addition Conjugated dienes undergo both 1,2 and 1,4 addition through an allylic intermediate. for example, 1,3-butadiene react with one molar equivalent of hydrogen chloride to give two products, 3-chloro-1-butene and 1-chloro-2-butadiene. Why? Dr. Dina akhotmah

17 The addition of HX undergo by allylic intermediate, the mechanism will give better understanding for this result Reaction Mechanism Dr. Dina akhotmah

18 Dr. Dina akhotmah

19 Dr. Dina akhotmah

20 1.2 addition 1.4 addition Dr. Dina akhotmah

21 Dr. Dina akhotmah

22 (Page 625) Dr. Dina akhotmah

23 Preparation of conjugated diene Dienes can be prepared by elimination reactions of unsaturated alcohols and alkyl halides. The outcome of eliminations typically favors the more stable product, Since conjugated dienes are more stable than isolated dienes, the formation of the conjugated diene is usually favored over the isolated diene unless the structure prevents the formation of the conjugated system. H H O R H R H 2 S O 4 K O H h e a t h e a t c o n j u g a t e d d i e n e s H H B R r What would the products of the following sequences be? Why? a) 1-butene reacted with N-bromosuccinimide (NBS) then treated with KOH / heat b) cyclohexene reacted with Br 2 / CH2Cl2 then with KOH / heat Dr. Dina akhotmah

24 a) H H H 2 C C C CH 3 NBS heat, Cl H 4 1-butene Br KOH, heat -HBr morestablediene b) Br Br 2 /Cl 4 KOH, heat -HBr Br KOH, heat -HBr Br Dr. Dina akhotmah

25 Dr. Dina akhotmah

26 Dr. Dina akhotmah

27 Class exercises Dr. Dina akhotmah

28 Preparation of isoprene O H C C H s t r o n g b a s e O H H O H C + + H 3 C C H 3 C C H H 3 C C C H 3 C C H H 2 / P d H 2 C A l 2 O 3 - H 2 O C C H 3 C H C H 2 p o l y m e r i z a t i o n H 2 C C H C C H 2 C H 3 i s o p r e n e Chemical structure of cis polyisoprene the main constituent of natural rubber Dr. Dina akhotmah

29 Terpenes Terpenes is made of isoprene unit (2-methyl-1,3-butadiene) linked in a head-to-tail fashion. (isoprene is a building block of terpenes). For example, Monoterpenes are consists of two isoprene units, They are volatile natural products found in higher plants as essential oils and are widely used in perfumery and flavouring industries. For example, Lemon oil and Myrcene Dr. Dina akhotmah

30 Dr. Dina akhotmah

31 Solomon's, page 616 Dr. Dina akhotmah

32 What Is the Diels-Alder Reaction? Heat 200 o C The reaction occurs via a concerted mechanism, meaning that it takes place all at once, with no isolatable intermediates. Dr. Dina akhotmah

33 Diels-alder reaction is favoured by presence of : a) Electron-releasing groups in the diene (e.g. -R, -OR) b) Electron-withdrawing groups in the dienophile, for example Maleic anhydride The easiest way to predict Diels-Alder products is to number the six carbons that make up the cyclohexene ring. Note: this is not a nomenclature numbering Dr. Dina akhotmah

34 The Diels-Alder is Stereospecific The Diels-Alder is a stereospecific reaction, because the stereochemistry of the dienophile is maintained in the cyclohexene product: a trans dienophile yields in the trans product, and a cis dienophile yields the cis product. What Can and Can t Undergo Diels-Alder? Only conjugated dienes in the s-cis conformation can undergo Diels-Alder reactions. If a diene is not conjugated, or can t be in the cis conformation, then it can t undergo a Diels- Alder reaction. Dienes that are located in rings can t rotate, and so are stuck in either an s-cis or s-trans conformation. But acyclic dienes can rotate into the s-cis conformation, as long as their substituents aren t too big/bulky to prevent easy rotation. Dr. Dina akhotmah

35 Retro Diels-Alder The Diels-Alder reaction is reversible. Going from cyclohexene to a diene and dienophile is called a retro Diels-Alder reaction. It s also a very common to be asked what starting materials produced this Diels-Alder product? The best strategy for determining retro Diels-Alder questions is also to number the cyclohexene ring. Below are some examples. Dr. Dina akhotmah

36 Dr. Dina akhotmah

37 Multiple Choice Quiz For a diene to undergo Diels-Alder reaction it must: a) be substituted with electron-withdawing groups. b) be able to adopt an s-trans conformation c) be substituted with electron-donating groups d) be able to adopt the s-cis conformation. What is the major product of the following reaction: None of the Above More questions and information's on chemheler.com Dr. Dina akhotmah

Organic Chemistry II / CHEM 252 Chapter 13 Conjugated Unsaturated Systems

Organic Chemistry II / CHEM 252 Chapter 13 Conjugated Unsaturated Systems Organic Chemistry II / CHEM 252 Chapter 13 Conjugated Unsaturated Systems Bela Torok Department of Chemistry University of Massachusetts Boston Boston, MA 1 Introduction - Conjugated unsaturated systems

More information

CHAPTER 9 THEORY OF RESONANCE BY, G.DEEPA

CHAPTER 9 THEORY OF RESONANCE BY, G.DEEPA CHAPTER 9 THEORY OF RESONANCE BY, G.DEEPA Conjugation in Alkadienes and Allylic Systems conjugation a series of overlapping p orbitals The Allyl Group allylic position is the next to a double bond 1 allyl

More information

Chapter 13 Conjugated Unsaturated Systems

Chapter 13 Conjugated Unsaturated Systems Chapter 13 Conjugated Unsaturated Systems Introduction Conjugated unsaturated systems have a p orbital on a carbon adjacent to a double bond The p orbital can come from another double or triple bond The

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

and Ultraviolet Spectroscopy

and Ultraviolet Spectroscopy Organic Chemistry, 7 th Edition L. G. Wade, Jr. Chapter 15 Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy 2010, Prentice all Conjugated Systems Conjugated double bonds are separated

More information

11/5/ Conjugated Dienes. Conjugated Dienes. Conjugated Dienes. Heats of Hydrogenation

11/5/ Conjugated Dienes. Conjugated Dienes. Conjugated Dienes. Heats of Hydrogenation 8.12 Sites of unsaturation Many compounds have numerous sites of unsaturation If sites are well separated in molecule they react independently If sites are close together they may interact with one another

More information

There are several possible arrangements for a molecule which contains two double bonds (diene): 1. Isolated: (two or more single bonds between them)

There are several possible arrangements for a molecule which contains two double bonds (diene): 1. Isolated: (two or more single bonds between them) 1 Chapter 15: Conjugation and Reactions of Dienes I. Introduction to Conjugation There are several possible arrangements for a molecule which contains two double bonds (diene): 1. Isolated: (two or more

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

Lecture Notes Chem 51B S. King I. Conjugation

Lecture 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 information

Conjugated Dienes and Ultraviolet Spectroscopy

Conjugated Dienes and Ultraviolet Spectroscopy Conjugated Dienes and Ultraviolet Spectroscopy Key Words Conjugated Diene Resonance Structures Dienophiles Concerted Reaction Pericyclic Reaction Cycloaddition Reaction Bridged Bicyclic Compound Cyclic

More information

Learning Guide for Chapter 17 - Dienes

Learning Guide for Chapter 17 - Dienes Learning Guide for Chapter 17 - Dienes I. Isolated, conjugated, and cumulated dienes II. Reactions involving allylic cations or radicals III. Diels-Alder Reactions IV. Aromaticity I. Isolated, Conjugated,

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

Chapter 13. Conjugated Unsaturated Systems. +,., - Allyl. What is a conjugated system? AllylicChlorination (High Temperature)

Chapter 13. Conjugated Unsaturated Systems. +,., - Allyl. What is a conjugated system? AllylicChlorination (High Temperature) What is a conjugated system? Chapter 13 Conjugated Unsaturated Systems Conjugated unsaturated systems have a p orbital on a carbon adjacent to a double bond The p orbital may be empty (a carbocation The

More information

Dienes & Polyenes: An overview and two key reactions (Ch )

Dienes & Polyenes: An overview and two key reactions (Ch ) Dienes & Polyenes: An overview and two key reactions (h. 14.1-14.5) Polyenes contain more than one double bond and are very common in natural products (ex: carotene). Diene chemistry applies to trienes,

More information

Exam. Name. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Exam. Name. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements is incorrect about benzene? 1) A) All of the carbon

More information

Conjugated Systems. With conjugated double bonds resonance structures can be drawn

Conjugated Systems. With conjugated double bonds resonance structures can be drawn Conjugated Systems Double bonds in conjugation behave differently than isolated double bonds With conjugated double bonds resonance structures can be drawn With isolated double bonds cannot draw resonance

More information

Conjugated Systems, Orbital Symmetry and UV Spectroscopy

Conjugated Systems, Orbital Symmetry and UV Spectroscopy Conjugated Systems, Orbital Symmetry and UV Spectroscopy Introduction There are several possible arrangements for a molecule which contains two double bonds (diene): Isolated: (two or more single bonds

More information

Homework for Chapter 17 Chem 2320

Homework for Chapter 17 Chem 2320 Homework for Chapter 17 Chem 2320 I. Cumulated, isolated, and conjugated dienes Name 1. Draw structures which fit the following descriptions. Use correct geometry! a conjugated diene with the formula C

More information

Chapter 14: Conjugated Dienes

Chapter 14: Conjugated Dienes Chapter 14: Conjugated Dienes Coverage: 1. Conjugated vs Nonconjugated dienes and Stability 2. MO picture of 1,3-butadiene 3. Electrophilic addition to Dienes 4. Kinetic vs Thermodynamic Control 5. Diels-Alder

More information

Chapter 15 Dienes, Resonance, and Aromaticity

Chapter 15 Dienes, Resonance, and Aromaticity Instructor Supplemental Solutions to Problems 2010 Roberts and Company Publishers Chapter 15 Dienes, Resonance, and Aromaticity Solutions to In-Text Problems 15.2 The delocalization energy is the energy

More information

3 - CONJUGATION. More than one double bond can be in a given compound: n=0

3 - CONJUGATION. More than one double bond can be in a given compound: n=0 3 - NJUGATIN 1. Terminology and Nomenclature (SF 13.1 13.6; SFS 13.1 13.6) A compound containing a double bond is called an alkene, olefin or maybe simply "ene". There are often other names associated

More information

ST. JOSEPH S COLLEGE OF ARTS & SCIENCE (AUTONOMOUS) ST. JOSEPH S COLLEGE ROAD, CUDDALORE CH101T ORGANIC CHEMISTRY I (SEMESTER-I)

ST. JOSEPH S COLLEGE OF ARTS & SCIENCE (AUTONOMOUS) ST. JOSEPH S COLLEGE ROAD, CUDDALORE CH101T ORGANIC CHEMISTRY I (SEMESTER-I) UNIT I 1. The hybridization involved in the formation of acetylene is a) sp b) sp 2 c) sp 3 d) sp 3 d 2. The IUPAC name of is 1. 3-hexene b) 4-hexene c) 3-hexyne d) 4-hexyne 3. -------- is the type of

More information

Reactions of Alkenes and Alkynes

Reactions of Alkenes and Alkynes 5 2 2 2 2 2 2 2 Reactions of Alkenes and Alkynes APTER SUMMARY Addition is the characteristic reaction of alkenes and alkynes. Since the carbons of a double or triple bond do not have the maximum number

More information

CHEM 347 Organic Chemistry II Spring Instructor: Paul Bracher. Quiz # 2

CHEM 347 Organic Chemistry II Spring Instructor: Paul Bracher. Quiz # 2 CHEM 347 Organic Chemistry II Spring 2015 Quiz # 2 Solutions Key Page 1 of 12 CHEM 347 Organic Chemistry II Spring 2015 Instructor: Paul Bracher Quiz # 2 Due: Monday, February 9 th, 2015 2:00 p.m. (in

More information

Diels-Alder Cycloaddition

Diels-Alder Cycloaddition Diels-Alder ycloaddition A lab practice for the reaction between cyclopentadiene and maleic anhydride The Diels-Alder ycloaddition + onjugated diene Dienophile Diels-Alder reaction: * Stereospecific *

More information

CHAPTER 3 ALKENES, ALKYNES & CONJUGATE DIENES

CHAPTER 3 ALKENES, ALKYNES & CONJUGATE DIENES CHEM 244 PRINCIPLES OF ORGANIC CHEMISTRY I FOR CHEMICAL ENGINEERING STUDENTS, COLLEGE OF ENGINEERING PRE-REQUISITES COURSE; CHEM 101 CREDIT HOURS; 2 (2+0) Dr. Mohamed El-Newehy Chemistry Department, College

More information

The C-X bond gets longerand weakergoing down the periodic table.

The C-X bond gets longerand weakergoing down the periodic table. Chapter 10: Organohalides Organic molecules containing halogen atoms (X) bonded to carbon are useful compounds in synthesis and on their own. 10.2 Structure of alkyl halides The C-X bond gets longerand

More information

Ch 14 Conjugated Dienes and UV Spectroscopy

Ch 14 Conjugated Dienes and UV Spectroscopy Ch 14 Conjugated Dienes and UV Spectroscopy Conjugated Systems - Conjugated systems have alternating single and double bonds. For example: C=C C=C C=C and C=C C=O - This is not conjugated because the double

More information

Diels-Alder Reaction

Diels-Alder Reaction Diels-Alder Reaction Method for synthesis of 6-membered ring ne-step, concerted reaction Termed [4+2] cycloaddition reaction where 4 and 2 electrons react. + Diels-Alder Reaction Discovered by. Diels and

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

Chapter 13 Conjugated Unsaturated Systems

Chapter 13 Conjugated Unsaturated Systems Conjugated Unsaturated Systems 13.1 Introduction Allyl radical C 2 C C 2 C C C Allyl cation C 2 C C 2 C C C 1,3-Butadiene C 2 C C C 2 C C C C Molecules with delocalized π bonds are called conjugated unsaturated

More information

3) The delocalized π system in benzene is formed by a cyclic overlap of 6 orbitals. A) s B) p C) sp D) sp2 E) sp3

3) The delocalized π system in benzene is formed by a cyclic overlap of 6 orbitals. A) s B) p C) sp D) sp2 E) sp3 Chapter 8 Questions 1) Which of the following statements is incorrect about benzene? A) All of the carbon atoms are sp hybridized. B) It has delocalized electrons. C) The carbon-carbon bond lengths are

More information

The Final Learning Experience

The Final Learning Experience Chemistry 210 Organic Chemistry I Fall Semester 2000 Dr. Rainer Glaser Examination #5 Reactions of Alcohols and Related Reactions The Final Learning Experience Wednesday, December 20, 2000, 1:00-3:00 Name:

More information

CHEMISTRY Topic #3: Addition Reactions of Conjugated Dienes Spring 2017 Dr. Susan Findlay

CHEMISTRY Topic #3: Addition Reactions of Conjugated Dienes Spring 2017 Dr. Susan Findlay CEMISTRY 2600 Topic #3: Addition Reactions of Conjugated Dienes Spring 2017 Dr. Susan Findlay Different Kinds of Dienes When a molecule contains multiple π-bonds, their reactivity is dictated in part by

More information

Chapter 12 Alkenes and Alkynes

Chapter 12 Alkenes and Alkynes BR M 102 lass Notes hapter 12 Page 1 of 8 hapter 12 Alkenes and Alkynes * alkenes = double bonds * alkynes triple bonds * aromatics or arenes alternating double and single bonds such as in benzene * saturated

More information

1. Which of the following reactions would have the smallest energy of activation?.

1. Which of the following reactions would have the smallest energy of activation?. Name: Date: 1. Which of the following reactions would have the smallest energy of activation?. A) +. +. B) + +. C) +.. + D) +.. + E) +.. + 2. Which of the following reactions would have the smallest energy

More information

Conjugated Systems & Pericyclic Reactions

Conjugated Systems & Pericyclic Reactions onjugated Systems & Pericyclic Reactions 1 onjugated Dienes from heats of hydrogenation-relative stabilities of conjugated vs unconjugated dienes can be studied: Name 1-Butene 1-Pentene Structural Formula

More information

2. Which functional groups and structural features are present in the following molecule (strychnine)?

2. Which functional groups and structural features are present in the following molecule (strychnine)? Chapter 1-2: 1. Which of the following species has a negative charge but NO lone pair of valance shell nonbonding electrons? [all atoms have complete valance shell of electrons, but lone pairs are not

More information

10. 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 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 information

Introduction to Alkenes and Alkynes

Introduction to Alkenes and Alkynes Introduction to Alkenes and Alkynes In an alkane, all covalent bonds between carbon were σ (σ bonds are defined as bonds where the electron density is symmetric about the internuclear axis) In an alkene,

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

CHAPTER 16 CONJUGATE ADDITION

CHAPTER 16 CONJUGATE ADDITION HAPTER 16 NJUGATE ADDITIN onjugated Pi Bonds onjugated double bonds are separated by only one single bond. Isolated double bonds are separated by two or more single bonds. arbonyl ompounds with onjugated

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

17.1 Classes of Dienes

17.1 Classes of Dienes 17.1 Classes of Dienes There are three categories for dienes: Cumulated: pi bonds are adjacent. Conjugated: pi bonds are separated by exactly ONE single bond. Isolated: pi bonds are separated by any distance

More information

Objective 5. Identify a conjugated diene and understand electrophilic addition reactions of dienes.

Objective 5. Identify a conjugated diene and understand electrophilic addition reactions of dienes. Objective 5. Identify a conjugated diene and understand electrophilic addition reactions of dienes. Skills: Draw structure ID structural features and reactive sites (alpha C, beta C, LG, etc.) ID Nu -

More information

10. Organohalides. Based on McMurry s Organic Chemistry, 7 th edition

10. 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 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

Loudon Chapter 15 Review: Dienes and Aromaticity Jacquie Richardson, CU Boulder Last updated 1/28/2019

Loudon Chapter 15 Review: Dienes and Aromaticity Jacquie Richardson, CU Boulder Last updated 1/28/2019 This chapter looks at the behavior of carbon-carbon double bonds when several of them are in the same molecule. There are several possible ways they can be grouped. Conjugated dienes have a continuous

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. A) I B) II C) III D) IV E) V

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. A) I B) II C) III D) IV E) V Practice Questions : Chem 226 / Exam 3 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements about benzene is correct?

More information

Replace one H with a Br for every mole of Br 2

Replace one H with a Br for every mole of Br 2 Substitution A substitution reaction occurs when a hydrogen atom is removed from a hydrocarbon and replaced by a halide substituent. When a bromine molecule absorbs energy, the covalent bond is broken

More information

Name: Student Number: University of Manitoba - Department of Chemistry CHEM Introductory Organic Chemistry II - Term Test 1

Name: Student Number: University of Manitoba - Department of Chemistry CHEM Introductory Organic Chemistry II - Term Test 1 Name: Student Number: University of Manitoba - Department of Chemistry CHEM 2220 - Introductory Organic Chemistry II - Term Test 1 Thursday, February 11, 2016; 7-9 PM This is a 2-hour test, marked out

More information

nsaturated Hydrocarbons: Alkenes, Cycloalkenes and Dienes

nsaturated Hydrocarbons: Alkenes, Cycloalkenes and Dienes 240 Chem nsaturated Hydrocarbons: Alkenes, Cycloalkenes and Dienes 1 Chapter 3 Alkenes or Olefines Crabon-Carbon double bond C n H 2n Hybridization in Alkenes: 1.34 A 2 Nomenclature of Alkenes and Cycloalkenes

More information

Organic Chemistry. Alkenes (2)

Organic Chemistry. Alkenes (2) For updated version, please click on http://ocw.ump.edu.my Organic Chemistry Alkenes (2) by Dr. Seema Zareen & Dr. Izan Izwan Misnon Faculty Industrial Science & Technology seema@ump.edu.my & iezwan@ump.edu.my

More information

DAV CENTENARY PUBLIC SCHOOL, PASCHIM ENCLAVE, NEW DELHI - 87

DAV CENTENARY PUBLIC SCHOOL, PASCHIM ENCLAVE, NEW DELHI - 87 HYDROCARBONS 1. Why do alkenes prefer to undergo electrophilic addition reaction while arenes prefer electrophilic substitution reactions? Explain. 2. Alkynes on reduction with sodium in liquid ammonia

More information

Chemistry 2000 Lecture 18: Reactions of organic compounds

Chemistry 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 information

12/27/2010. Chapter 15 Reactions of Aromatic Compounds

12/27/2010. 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 information

Unsaturated hydrocarbons. Chapter 13

Unsaturated hydrocarbons. Chapter 13 Unsaturated hydrocarbons Chapter 13 Unsaturated hydrocarbons Hydrocarbons which contain at least one C-C multiple (double or triple) bond. The multiple bond is a site for chemical reactions in these molecules.

More information

Organic Chemistry, Second Edition. Janice Gorzynski Smith University of Hawai i. Chapter 10 Alkenes

Organic Chemistry, Second Edition. Janice Gorzynski Smith University of Hawai i. Chapter 10 Alkenes Organic Chemistry, Second Edition Janice Gorzynski Smith University of Hawai i Chapter 10 Alkenes Prepared by Rabi Ann Musah State University of New York at Albany Copyright The McGraw-Hill Companies,

More information

Review and Preview. Coursepack: pp (14.6 is FYI only)

Review and Preview. Coursepack: pp (14.6 is FYI only) Review and Preview We have studied many compounds with pi bonds. When a compound has more than one multiple bond in its structure, the relative positions of those multiple bonds with respect to one another

More information

Organic Chemistry II KEY March 25, a) I only b) II only c) II & III d) III & IV e) I, II, III & IV

Organic Chemistry II KEY March 25, a) I only b) II only c) II & III d) III & IV e) I, II, III & IV rganic Chemistry II KEY March 25, 2015 Exam 2: VERSIN A 1. Which of the following compounds will give rise to an aromatic conjugate base? E a) I only b) II only c) II & III d) III & IV e) I, II, III &

More information

2016 Pearson Education, Inc. Isolated and Conjugated Dienes

2016 Pearson Education, Inc. Isolated and Conjugated Dienes 2016 Pearson Education, Inc. Isolated and Conjugated Dienes 2016 Pearson Education, Inc. Reactions of Isolated Dienes 2016 Pearson Education, Inc. The Mechanism Double Bonds can have Different Reactivities

More information

CEM 351 3rd EXAM/Version A Friday, November 21, :50 2:40 p.m. Room 138, Chemistry

CEM 351 3rd EXAM/Version A Friday, November 21, :50 2:40 p.m. Room 138, Chemistry Name (print) Signature Student # Section Number CEM 351 3rd EXAM/Version A Friday, November 21, 2003 1:50 2:40 p.m. Room 138, Chemistry Key Grade? 1.(20 2.(20. 3.(20 4.(20 5.(20 6.(20 TTAL 100 Score Note:

More information

Conjugated Dienes. Chapter 14 Organic Chemistry, 8 th Edition John E. McMurry

Conjugated Dienes. Chapter 14 Organic Chemistry, 8 th Edition John E. McMurry Conjugated Dienes Chapter 14 Organic Chemistry, 8 th Edition John E. McMurry 1 Dienes Propadiene (allene) is a cumulated diene 1,3-Butadiene is a conjugated diene. 1,4-Pentadiene is an isolated diene.

More information

Columbia University 92CORG14.DOC CHEM S3443D Summer 1992 Professor Grace B. Borowitz Exam No. 4 July 2, 1992

Columbia University 92CORG14.DOC CHEM S3443D Summer 1992 Professor Grace B. Borowitz Exam No. 4 July 2, 1992 olumbia University 92RG14.D EM S3443D Summer 1992 Professor Grace B. Borowitz Exam No. 4 July 2, 1992 Name: Grade: Please use a non-red pen. Answer questions in the provided space. If you write any answers

More information

Ethers. Chapter 14: Ethers, Epoxides, & Sulfides. General Formula: Types: a) Symmetrical: Examples: b) Unsymmetrical: Examples: Physical Properties:

Ethers. Chapter 14: Ethers, Epoxides, & Sulfides. General Formula: Types: a) Symmetrical: Examples: b) Unsymmetrical: Examples: Physical Properties: Chamras Chemistry 106 Lecture Notes Examination 1 Materials Chapter 14: Ethers, Epoxides, & Sulfides Ethers General Formula: Types: a) Symmetrical: Examples: b) Unsymmetrical: Examples: Physical Properties:

More information

Chem 263 Sept 22, Beta-carotene (depicted below) is the orange-red colour in carrots. β-carotene

Chem 263 Sept 22, Beta-carotene (depicted below) is the orange-red colour in carrots. β-carotene hem 263 Sept 22, 2009 onjugated Dienes and olour ontinued Beta-carotene (depicted below) is the orange-red colour in carrots. Xanthophylls β-carotene Xanthophylls are oxygenated carotene molecules. Zeaxanthin,

More information

10.12 The Diels-Alder Reaction. Synthetic method for preparing compounds containing a cyclohexene ring

10.12 The Diels-Alder Reaction. Synthetic method for preparing compounds containing a cyclohexene ring 10.12 The Diels-Alder Reaction Synthetic method for preparing compounds containing a cyclohexene ring In general... + conjugated diene alkene (dienophile) cyclohexene via transition state Mechanistic features

More information

CYCLOADDITIONS IN ORGANIC SYNTHESIS

CYCLOADDITIONS IN ORGANIC SYNTHESIS CYCLOADDITIONS IN ORGANIC SYNTHESIS 1 CYCLOADDITIONS IN ORGANIC SYNTHESIS Introduction Cycloaddition describes the union of two independent π-systems through a concerted process involving a cyclic movement

More information

Chem 261 Nov 20, Conjugated = separated by a single bond from a double bond

Chem 261 Nov 20, Conjugated = separated by a single bond from a double bond 7 hem 6 Nov 0, 07 REVIEW: onjugated = separated by a single bond from a double bond Examples of onjugated Systems. Double bonds ( or more). Allylic ations. Allylic Anions. Allylic Radicals REVIEW: Molecules

More information

Part Define s-p overlapping. [When s orbital of an atom overlaps with p orbital of another atoms]

Part Define s-p overlapping. [When s orbital of an atom overlaps with p orbital of another atoms] Program Name B.Sc. (Chemistry) B.Sc. - Part I Paper Code CH- 02 (Organic chemistry) Section A (Very Short Answer Questions 2 Each Question Carries 2 Marks Part -1 1. Define s-p overlapping. [When s orbital

More information

Organic Mechanisms 1

Organic 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 information

Chapter 15 Reactions of Aromatic Compounds

Chapter 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 information

Conjugated Systems. Organic Compounds That Conduct Electricity

Conjugated Systems. Organic Compounds That Conduct Electricity Conjugated Systems Organic Compounds That Conduct Electricity Conjugated and Nonconjugated Dienes Compounds can have more than one double or triple bond If they are separated by only one single bond they

More information

COURSE UNIT DESCRIPTION. Type of the course unit. Mode of delivery Period of delivery Language of instruction Face to face Autumn English

COURSE UNIT DESCRIPTION. Type of the course unit. Mode of delivery Period of delivery Language of instruction Face to face Autumn English Course unit title Organic Chemistry I Lecturer(s) Dr. Rimantas Vaitkus COURSE UNIT DESCRIPTION Department Dept. Organic Chemistry, Vilnius University Cycle First Type of the course unit Mode of delivery

More information

Organic Chemistry. REACTIONS Grade 12 Physical Science Mrs KL Faling

Organic Chemistry. REACTIONS Grade 12 Physical Science Mrs KL Faling Organic Chemistry REACTIONS Grade 12 Physical Science Mrs KL Faling SUBSTITUTION REACTIONS This is a reaction where an atom or group of atoms is replaced by another atom or group of atoms Substitution

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

Name: Student Number: University of Manitoba - Department of Chemistry CHEM Introductory Organic Chemistry II - Term Test 1

Name: Student Number: University of Manitoba - Department of Chemistry CHEM Introductory Organic Chemistry II - Term Test 1 Name: Student Number: University of Manitoba - Department of Chemistry CHEM 2220 - Introductory Organic Chemistry II - Term Test 1 Thursday, February 12, 2015; 7-9 PM This is a 2-hour test, marked out

More information

PAPER No. 5: REACTION MECHANISM MODULE No. 2: Types of Organic Reaction Mechanisms

PAPER 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 information

Vision. Cis-trans isomerism is key to vision. How rods work H 3 C CH 3. Protein opsin. 11-cis-retinal. Opsin. Rhodopsin.

Vision. Cis-trans isomerism is key to vision. How rods work H 3 C CH 3. Protein opsin. 11-cis-retinal. Opsin. Rhodopsin. Vision Cis-trans isomerism is key to vision. 3 C 11 12 3 C C 3 3 C O C 3 11-cis-retinal Protein opsin 3 C 11 12 3 C C 3 3 C N Opsin C 3 Rhodopsin Light photons 3 C N Opsin 3 C 11 12 3 C C 3 C 3 ow rods

More information

Chapter 4: Aromatic Compounds. Bitter almonds are the source of the aromatic compound benzaldehyde

Chapter 4: Aromatic Compounds. Bitter almonds are the source of the aromatic compound benzaldehyde Chapter 4: Aromatic Compounds Bitter almonds are the source of the aromatic compound benzaldehyde Sources of Benzene Benzene, C 6 H 6, is the parent hydrocarbon of the especially stable compounds known

More information

Lecture 24 Two Germans and an Englishman

Lecture 24 Two Germans and an Englishman Lecture 24 Two Germans and an Englishman Robert Robinson 1886-1975 Nobel Laureate 1947 April 17, 2018 tto Paul Hermann Diels 1876-1954 Nobel Laureates 1950 Kurt Alder 1902-1958 Exam III Tomorrow Wed April

More information

Conjugated Dienes. Chapter 14 Organic Chemistry, 8 th Edition John E. McMurry

Conjugated Dienes. Chapter 14 Organic Chemistry, 8 th Edition John E. McMurry Conjugated Dienes Chapter 14 Organic Chemistry, 8 th Edition John E. McMurry 1 Dienes Propadiene (allene) is a cumulated diene 1,3-Butadiene is a conjugated diene. 1,4-Pentadiene is an isolated diene.

More information

Learning Guide for Chapter 11 - Alkenes I

Learning Guide for Chapter 11 - Alkenes I Learning Guide for Chapter 11 - Alkenes I I. Introduction to alkenes - p 1 bond structure, classifying alkenes, reactivity, physical properties, occurrences and uses, spectroscopy, stabilty II. Unsaturation

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 3 Alkenes and Alkynes. Excluded sections 3.15&3.16

Chapter 3 Alkenes and Alkynes. Excluded sections 3.15&3.16 Chapter 3 Alkenes and Alkynes Excluded sections 3.15&3.16 3.1 Definition and Classification Alkene: a hydrocarbon that contains one or more carboncarbon double bonds. ethylene is the simplest alkene. Alkyne:

More information

Module9. Nuclear Magnetic Resonance Spectroscopy Nuclear Magnetic Resonance (NMR) spectroscopy - Chemical shift - Integration of signal area

Module9. Nuclear Magnetic Resonance Spectroscopy Nuclear Magnetic Resonance (NMR) spectroscopy - Chemical shift - Integration of signal area 1 CHEMISTRY 263 HOME WORK Lecture Topics: Module7. Hydrogenation of Alkenes The Function of the Catalyst - Syn and anti- addition Hydrogenation of Alkynes - Syn- addition of hydrogen: Synthesis of cis-alkenes

More information

CHEMISTRY 263 HOME WORK

CHEMISTRY 263 HOME WORK Lecture Topics: CHEMISTRY 263 HOME WORK Module7: Hydrogenation of Alkenes Hydrogenation - syn and anti- addition - hydrogenation of alkynes - synthesis of cis-alkenes -synthesis of trans-alkenes Text sections:

More information

Chapter 8 Outline: Alkenes: Structure and Preparation via β-elimination

Chapter 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 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

Class XI Chapter 13 Hydrocarbons Chemistry

Class XI Chapter 13 Hydrocarbons Chemistry Question 13.1: How do you account for the formation of ethane during chlorination of methane? Chlorination of methane proceeds via a free radical chain mechanism. The whole reaction takes place in the

More information

Chapter 6 H 2 H 3 C C H CH 3 C H H 2 C C CH 3. (b) =2 H 2 C C C H H C H CH 2 C CH 3 H 3 C C C CH 3. (c) =2

Chapter 6 H 2 H 3 C C H CH 3 C H H 2 C C CH 3. (b) =2 H 2 C C C H H C H CH 2 C CH 3 H 3 C C C CH 3. (c) =2 hapter 6 6.1 alculate the degree of the unsaturation in the following hydrocarbons: 8 14 ; 5 6 (c) 12 20 (d) 20 32 (e) 40 56 =2 =3 (c) =3 (d) =5 (e) =13 6.2 alculate the degree of the unsaturation in the

More information

Key ideas: In EAS, pi bond is Nu and undergoes addition.

Key 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 information

Chapter 27 Pericyclic Reactions

Chapter 27 Pericyclic Reactions Instructor Supplemental Solutions to Problems 2010 Roberts and Company Publishers Chapter 27 Pericyclic Reactions Solutions to In-Text Problems 27.1 (b) This is a sigmatropic reaction; two electrons are

More information

Straight. C C bonds are sp 3 hybridized. Butane, C 4 H 10 H 3 C

Straight. C C bonds are sp 3 hybridized. Butane, C 4 H 10 H 3 C Hydrocarbons Straight Chain Alkanes aren t Straight C C bonds are sp 3 hybridized Butane, C 4 H 10 Structural Shorthand Explicit hydrogens (those required to complete carbon s valence) are usually left

More information

How alkyl halides react

How 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 information

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.

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. 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 information

17.1 Classes of Dienes

17.1 Classes of Dienes W 2/1 Due: HW14, spec03 Due: n/a M 2/6 Lecture HW14 grading Lect17a Conjugated π systems Lecture quiz Lect17b Lab Lab02 Qual Analysis II (cont) 7-1 17.1 Classes of Dienes There are three categories for

More information

Ch.6 Alkenes: Structure and Reactivity

Ch.6 Alkenes: Structure and Reactivity alkene = olefin 2 2 Ethylene α-pinene 3 β-arotene (orange pigment and vitamin A precursor) 6.1 Industrial Preparation and Use of Alkenes ompounds derived industrially from ethylene 2 2 Ethylene (26 million

More information

CHEMISTRY MIDTERM # 2 ANSWER KEY July 10, 2002

CHEMISTRY MIDTERM # 2 ANSWER KEY July 10, 2002 EMISTRY 314-81 MIDTERM # 2 ANSWER KEY July 10, 2002 Statistics: Average: 47 pts (67%); ighest: 69 pts (99%); Lowest: 26 pts (37%) Number of students performing at or above average: 12 (46%) 1. (7 pts)

More information

Chapter 15. Reactions of Aromatic Compounds. Electrophilic Aromatic Substitution on Arenes. The first step is the slow, rate-determining step

Chapter 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 information