Chapter 16: Chemistry of Benzene: Electrophilic Aromatic Substitution. Let us look at bromination: δ+ δ Br Br FeBr 3 Br Br FeBr 3

Size: px
Start display at page:

Download "Chapter 16: Chemistry of Benzene: Electrophilic Aromatic Substitution. Let us look at bromination: δ+ δ Br Br FeBr 3 Br Br FeBr 3"

Transcription

1 Chapter 16: Chemistry of Benzene: lectrophilic Aromatic Substitution lectrophilic positively charged species searching for electron density Aromatic benzene ring with a high electron density Substitution the overall reaction is the replacement of by the electrophile S 3 Sulfonation Let us look at bromination: 3 itration Alkylation Benzene omobenzene, 80% X alogenation Acylation The Lewis Acid catalyst is required to create the strong electrophile The addition stage: δ δ 3 3 omine (a weak electrophile) Polarized bromine (a strong electrophile) resonance stabilized This can also simply be shown as 4 -

2 What does the energy profile look like for this reaction? The elimination stage: 4 3 substitution occurs rather than addition since the elimination of the proton recreates the aromatic ring, with its superior stability. The other halogenations 86% 3 I I 65% Cu I I 86% 3 for iodine, an oxidant is needed itration 3 85% S 4 60 fluorine does not work too reactive! S 3 S 4 3 i Sn, ii a itrobenzene Aniline, 95% 3 this is an important reaction in the synthesis of substituted benzenes we will discuss this (Ch 4) at the end of this segment

3 Sulfonation S 3 S 4 40 S 3 95% S S 3 S S 4 S B S 3 S 3 Benzenesulfonic acid one advantage of sulfonation is that it is readily reversed: it is therefore easy to perform this reaction in either direction: S 3 S 3 S S 3 no water; low temp 40 95% S 4 S 3 S 3 and: S 3 S 4 S 4 95% 100 lots of water; high temp ne useful synthetic transformation of sulfonic acids: Alkylation of benzene rings: the Friedel Crafts alkylation C 3 S 3 i a, 300 ii 3 C 3 p-toluenesulfonic acid p-cresol, 7% Al 3 85% Benzene -Chloropropane Cumene (isopropylbenzene)

4 Al 3 Al 4 Limitations: An electron pair from the aromatic ring attacks the carbocation, forming a C-C bond and yielding a new carbocation intermediate Al 4 Al 4 1 An aryl halide T reactive Why not? A vinyl halide Loss of a proton then gives the neutral alkylated substitution product Al 3 X Al 3 reaction where = - 3, -, -C -S 3, -C, -CC 3, -C, -C C 3, (-, -, - ) Limitations: Acylation of benzene rings: the Friedel Crafts acylation 3 C(C 3) 3 C(C 3) 3 (C 3) 3C Al 3 C(C 3) 3 Al 3 80 Major product Minor product Benzene Acetyl chloride Acetophenone, 95% 4 C 3C C C CC C 3 Al 3 0 C 3 C C C C 3 sec-butylbenzene 65% Butylbenzene 35% o rearrangements -- multiple substitutions BBut the same limitations apply on substituents in the ring u t Al 3 Al 4 Substituents already present in the ring affect the substitution An acyl cation Al 3 Al 4

5 rientation of itration in Substituted Benzenes Meta-directing deactivators (C 3 ) C 76 C C t CC C product (%) o- m- p- 3 S 4 5 product (%) o- m- p- rtho- and para-directing deactivators F I rtho- and para-directing activators C CC benzene S 3 C C F alkyl C 3 eactivity 3 C CC 3 CC 3 I Ph CC 3 Meta-directing deactivators rtho- and para-directing deactivators rtho- and para-directing activators Substituents have two types of electronic effects inductive δ δ X δ δ δ C δ δ X δ δ δ δ δ C resonance (X = F,,, I) the groups attached to the ring are inductively electronwithdrawing because of the polarity of their bonds ings substituted by a group with an electron-withdrawing resonance effect have this general structure otice that for these groups all carbonyl groups, nitro, nitrile and sulfonic acid both inductive and resonance effects have the same result deactivation of the ring by electron withdrawal. benzaldehyde What happens when the two effects do not work in the same direction? inductive -- withdrawal δ δ resonance donation (X =halogen) ings substituted by a group with an electron-donating resonance effect have this general structure X otice these all have at least one electron pair on the atom directly attached to the ring Basically the stronger one wins! C 3 Alkyl group; inductively electron-donating

6 Directing effects those groups which send to the ortho- and para- positions Activating and deactivating effects summarized: eactivity 50% ortho Most stable meta 0% withdraws electrons; carbocation intermediate is less stable, and ring is less reactive donates electrons; carbocation intermediate is more stable, and ring is more reactive para 50% Most stable Directing effects those groups which send to the meta- positions Substituent ffects in lectrophilic Aromatic Substitution ortho 19% C Least stable C C Substituent eactivity rientation Inductive ffect esonance ffect C 3 activating o-/pweak electron-donating none activating o-/p- weak electron-withdrawing strong electron-donating C meta 7% C C C F I (C 3) 3 deactivating deactivating o-/p- m- strong electron-withdrawing strong electron-withdrawing weak electron-donating none para C C C C CC 3 C C t C deactivating m- strong electron-withdrawing strong electron-withdrawing 9% Least stable lectrophilic aromatic substitution in multiply substituted rings % lectrophilic aromatic substitution in multiply substituted rings C 3 C 0 C 3 80% Priorities: activator takes precedence over deactivator Priorities: activator takes precedence over deactivator strong activator takes precedence over weaker activator

7 lectrophilic aromatic substitution in multiply substituted rings C 3 3 C 3 C 3 S 4 C 3 98% Priorities: activator takes precedence over deactivator strong activator takes precedence over weaker activator all else being equal, steric constraints will dominate ucleophilic Aromatic Substitution - only proceeds when there is an activating substituent - since the ring bears a negative charge in the intermediate, electron withdrawing groups will stabilize and facilitate the reaction - this is the opposite of electrophilic reactions (positive intermediates)

8 eactions at the side chain of aromatic compounds oxidation C C C C 3 KMn 4 C Industrially: C 3 C butylbenzene benzoic acid 85% C 3 Co(III) C also K Cr 7,,, heat p-xylene terephthalic acid a few more examples eactions at the side chain of aromatic compounds a Cr 7 bromination S 4 85% Co(Ac), Ac 91% propylbenzene C C C 3 (PhC) C4 CC C 3 (1-bromopropyl)benzene 97% Co(Ac), Ac 90% refer back to 10.5 allylic bromination Ph Ph Ph why only the benzylic position? Ph benzyl radical resonance stabilized

9 where did the come from? some other examples: C 3 BS C C 4 hν 90% C 3 BS C 4 hν C 59% hν can replace (PhC ) And finally, reduction reactions of aromatics C 3C 3C CC C 3 Pd C C C 3 C 3 C 3, Pt, t 000 psi, 5 C 3 C 3 Al 3 propiophenone 95% propylbenzene 100% o-xylene 1,-dimethylcyclohexane 100% Al 3 C 3C 3C - C C C 3 C 3 CC 3 mixture of two products C 3 C 3 C 3 4-t-butylphenol, h/c, t 1 atm, 5 C 3 C 3 C 3 4-t-butylcyclohexanol 100% C 3 m-nitroacetophenone Pd/C t C 3 m-ethylaniline Strategy in aromatic substitution Strategy in aromatic substitution Things to consider: -- order in which groups are introduced this is dependent on the orientation in the target -- you may need to block a certain position to get the desired substitution pattern -- you may need to introduce a group to get the desired orientation, then modify it to the desired one called Functional Group Interconversion, FGI Things to consider: -- order in which groups are introduced

10 Strategy in aromatic substitution Functional Group Interconversions Things to consider: -- you may need to introduce a group to get the desired orientation, then modify it to the desired one meta- director ortho- / para- director 3 S 4 Pd/C t can be in these examples FGI nitro and amino This is a reduction -- most common reducing agents will work FGI nitro and amino, i Me 9% We can do a selective reduction i, ii a 95% i Sn, S, 3 t 80% ii a 8% LA in TF will also work, but the above processes are much cheaper! FGI nitro and amino FGI carbonyl and alkyl we have seen this one: This is an oxidation -- there is a mild, and specific, reagent Pd/C t CF 3 C 3 C 0 to 5 90% and this one follows on from a recent reaction: BS C 4 hν

11 There are two practice syntheses in the text problems 16.4 and 16.5 C both groups are ortho-/para- directing, so that s K but, we will never be able to get two large groups to substitute ortho- to each other in good yield Let us look at two different ones therefore, we must block the para- position in order to achieve ortho- substitution S 3 3 S and are in the correct orientation, if is introduced first 3 S S 4 S 4 heat but the will not be introduced in the correct orientation unless is changed to a stronger o/p director to is easy, but there is a problem with the latter it is too reactive (polysubstitution) and can react with an acid catalyst (to give a meta- director) 3 S 4 heat Pd/C t Ac py Ac Ac CF 3 C 3 C

Benzene does not undergo electrophilic addition. It undergoes electrophilic aromatic substitution maintaining the aromatic core

Benzene does not undergo electrophilic addition. It undergoes electrophilic aromatic substitution maintaining the aromatic core Substitution Reactions of Benzene and Its Derivatives Benzene does not undergo electrophilic addition It undergoes electrophilic aromatic substitution maintaining the aromatic core Electrophilic aromatic

More information

4/18/2011. 9.8 Substituent Effects in Electrophilic Substitutions. Substituent Effects in Electrophilic Substitutions

4/18/2011. 9.8 Substituent Effects in Electrophilic Substitutions. Substituent Effects in Electrophilic Substitutions 9.8 Substituent effects in the electrophilic substitution of an aromatic ring Substituents affect the reactivity of the aromatic ring Some substituents activate the ring, making it more reactive than benzene

More information

Reaction Coordinate Diagrams for the Two Benzene Reactions

Reaction Coordinate Diagrams for the Two Benzene Reactions Organic Chemistry 8 th Edition Paula Yurkanis Bruice Aromatic compounds such as benzene undergo electrophilic aromatic substitution reactions: Chapter 18 Reactions of Benzene and Substituted Benzenes Cap.

More information

Lecture Notes Chem 51B S. King. Chapter 18 Electrophilic Aromatic Substitution

Lecture Notes Chem 51B S. King. Chapter 18 Electrophilic Aromatic Substitution Lecture otes Chem 51B S. King Chapter 18 Electrophilic Aromatic Substitution I. Electrophilic Aromatic Substitution The most characteristic reaction of aromatic compounds is electrophilic aromatic substitution,

More information

Chapter 17: Reactions of Aromatic Compounds

Chapter 17: Reactions of Aromatic Compounds Chapter 17: Reactions of Aromatic Compounds Electrophilic aromatic substitution (17-1) Most common (normal) reaction of aromatics HNO 3 H 2 SO 4 NO 2 + H2O 452 Similar to alkenes, benzene (aromatics) has

More information

The Effect of Substituents on Reactivity

The Effect of Substituents on Reactivity The Effect of Substituents on Reactivity Substituents that donate electron density to the benzene ring increase benzene s nucleophilicity and stabilize the carbocation intermediate. Substituents that withdraw

More information

Chapter 16 Chemistry of Benzene. A. Electrophillic aromatic substitution of benzene rings

Chapter 16 Chemistry of Benzene. A. Electrophillic aromatic substitution of benzene rings A. Electrophillic aromatic substitution of benzene rings 1. Monosubstitution - If compound does electrophilic substitution rather than addition it is most likely aromatic. - some possibilities Addition

More information

KOT 222 ORGANIC CHEMISTRY II CHAPTER 17. REACTIONS of AROMATIC COMPOUNDS

KOT 222 ORGANIC CHEMISTRY II CHAPTER 17. REACTIONS of AROMATIC COMPOUNDS KOT 222 ORGANIC CEMISTRY II CAPTER 17 REACTIONS of AROMATIC COMPOUNDS 1 Electrophilic Aromatic Substitution Substitution of an electrophile for a proton on the aromatic ring. benzene s pi electrons are

More information

19.2 Halogenation 4/18/2012. Is the reaction substitution, elimination, addition or pericyclic?

19.2 Halogenation 4/18/2012. Is the reaction substitution, elimination, addition or pericyclic? 19.1 Introduction to Electrophilic Aromatic Substitution In Chapter 18, we saw how aromatic C=C double bonds are less reactive than typical alkene double bonds. Consider a bromination reaction: 19.1 Introduction

More information

Chapter 12: Reactions of Arenes: Electrophilic Aromatic Substitution 12.1: Representative Electrophilic Aromatic Substitution Reactions of Benzene

Chapter 12: Reactions of Arenes: Electrophilic Aromatic Substitution 12.1: Representative Electrophilic Aromatic Substitution Reactions of Benzene hapter 12: eactions of Arenes: Electrophilic Aromatic Substitution 12.1: epresentative Electrophilic Aromatic Substitution eactions of Benzene E= -, -, -I (halogenation) - 2 (nitration) -S 3 (sulfonation)

More information

508 CHAPTER TWELVE Reactions of Arenes: Electrophilic Aromatic Substitution O O BF 3. Acetic anhydride H H

508 CHAPTER TWELVE Reactions of Arenes: Electrophilic Aromatic Substitution O O BF 3. Acetic anhydride H H 508 CAPTR TWLV Reactions of s: lectrophilic Aromatic Substitution C3 CCC 3 BF 3 CC C 3 C 3 Furan Acetic anhydride 2-Acetylfuran (75 92%) Acetic acid The regioselectivity of substitution in furan is explained

More information

AROMATICITY. Chapter 8 REACTIONS OF BENZENE ORGANIC CHEMISTRY, 2 ND EDITION PAULA YURKANIS BRUICE

AROMATICITY. Chapter 8 REACTIONS OF BENZENE ORGANIC CHEMISTRY, 2 ND EDITION PAULA YURKANIS BRUICE ORGANIC CHEMISTRY, 2 ND EDITION PAULA YURKANIS BRUICE Chapter 8 AROMATICITY REACTIONS OF BENZENE RAED M. AL-ZOUBI, ASSISTANT PROFESSOR OF CHEMISTRY DEPARTMENT OF CHEMISTRY - N 4 L 0 JORDAN UNIVERSITY OF

More information

Electrophilic Aromatic Substitution Reactions

Electrophilic Aromatic Substitution Reactions Electrophilic Aromatic Substitution Reactions, Course Notes Archive, 1 Electrophilic Aromatic Substitution Reactions An organic reaction in which an electrophile substitutes a hydrogen atom in an aromatic

More information

Aromatic compounds are less reactive than many other molecules because of their stability

Aromatic compounds are less reactive than many other molecules because of their stability rganic Chemistry otes by Jim Maxka C 16: Reactions of Aromatic Compounds Topics: Aromatic compounds are less reactive than many other molecules because of their stability Formation of very T electrophiles

More information

Carbocations are electrophiles, and can therefore be useful reagents for forming new C-C bonds in EAS processes.

Carbocations are electrophiles, and can therefore be useful reagents for forming new C-C bonds in EAS processes. 1 (Continuation of Chapter 17 ) VIII. Friedel-Crafts Alkylation Carbocations are electrophiles, and can therefore be useful reagents for forming new C-C bonds in EAS processes. Friedal and Craft demonstrated

More information

Chemistry 232 Summer 2016 Quiz 2a

Chemistry 232 Summer 2016 Quiz 2a 1 Chemistry 232 Summer 2016 Quiz 2a KEY Name: (Please print, surname first) ID: Do all questions. Time available: 20 min. Total available marks: 20. Score for this quiz: Answers written partially or completely

More information

Benzene Benzene is best represented as a resonance hybrid:

Benzene Benzene is best represented as a resonance hybrid: Electrophilic Aromatic Substitution (EAS) is a substitution reaction usually involving the benzene ring; more specifically it is a reaction in which the hydrogen atom of an aromatic ring is replaced as

More information

Chapter 19 Aromatic Substitution Reactions

Chapter 19 Aromatic Substitution Reactions Chapter 19 Aromatic Substitution Reactions Review of Concepts Fill in the blanks below. To verify that your answers are correct, look in your textbook at the end of Chapter 19. Each of the sentences below

More information

Reactions of Aromatic Compounds

Reactions of Aromatic Compounds 2-1 Reactions of Aromatic Compounds 15.1 2-2 lectrophilic Aromatic Substitution Reactions Aromatic hydrocarbons (= arenes) undergo a substitution reaction with electrophiles: + catalyst + xample: omination

More information

REACTIONS OF AROMATIC COMPOUNDS

REACTIONS OF AROMATIC COMPOUNDS A STUDET SULD BE ABLE T: REACTIS F ARMATIC CMPUDS 1. Predict the product(s) of Electrophilic Aromatic Substitution (EAS), ucleophilic Aromatic Substitution (S Ar), Elimination-Addition reactions, and side-chain

More information

Chapter 16: Chemistry of Benzene: Electrophilic Aromatic Substitution

Chapter 16: Chemistry of Benzene: Electrophilic Aromatic Substitution rganic Chemistry Lecture utline I. ELECTPILIC AMATIC UBTITUTIN (EA) A. There are five general types of electrophilic aromatic substitution reactions. 1. alogenation of benzene with Br 2, Cl 2 or I 2 occurs

More information

Reactions of Benzene & Its Derivatives

Reactions of Benzene & Its Derivatives rganic Lecture Series Reactions of Benzene & Its Derivatives Chapter 22 1 Reactions of Benzene rganic Lecture Series The most characteristic reaction of aromatic compounds is substitution at a ring carbon

More information

Friedel Crafts Acylation

Friedel Crafts Acylation Friedel Crafts Acylation An acyl chloride or an acid anhydride is the source of the acyl group. A Lewis acid (AlCl 3 ) is required. The Mechanism for Friedel Crafts Acylation The electrophile adds to the

More information

Chapter 8. Aromaticity

Chapter 8. Aromaticity Chapter 8. Aromaticity Learning objectives: 1. Name benzene derivatives. 2. Recognize aromatic compounds. 3. Explain the trend for the acidity of substituted phenol using the concept of electrondonating

More information

Reactions of Aromatic Compounds

Reactions of Aromatic Compounds Reactions of Aromatic Compounds Aromatic compounds are stabilized by this aromatic stabilization energy Due to this stabilization, normal S N 2 reactions observed with alkanes do not occur with aromatic

More information

Reactions of Aromatic Compounds

Reactions of Aromatic Compounds Chapter 17 Reactions of Aromatic Compounds Organic Chemistry, 8 th Edition L. G. Wade, Jr. Prof. Jeong Woo Han Department of Chemical Engineering jwhan@uos.ac.kr Reactions of Aromatic Compounds Key Contents

More information

Aromatic Compounds: Compounds that resemble benzene in structure and. chemical behavior (terms comes from fragrant odors)

Aromatic Compounds: Compounds that resemble benzene in structure and. chemical behavior (terms comes from fragrant odors) III Aromatic Compounds Aromatic Compounds: chemical behavior (terms comes from fragrant odors) Compounds that resemble benzene in structure and Benzene: - Cyclic Compound - Six-Membered Ring - ONLY Six

More information

CH 2 CHCH 3. (a) 1-bromo-3-chlorobenzene or m-bromochlorobenzene. (b) isobutylbenzene. (c) p-bromoaniline or 4-bromoaniline.

CH 2 CHCH 3. (a) 1-bromo-3-chlorobenzene or m-bromochlorobenzene. (b) isobutylbenzene. (c) p-bromoaniline or 4-bromoaniline. Chem 226 Problem Set #5 Fundamentals of rganic Chemistry, 4 th edition, John McMurry. Chapter 5 4. Give IUPAC names for the following compounds. C 2 C N 2 (b) (c) 1-bromo-3-chlorobenzene or m-bromochlorobenzene.

More information

Lecture 8. Friedel-Crafts reaction: Mechanism: Carbocation is the reactive electrophile. AlCl4- picks up a proton.

Lecture 8. Friedel-Crafts reaction: Mechanism: Carbocation is the reactive electrophile. AlCl4- picks up a proton. New Section 3 Page 1 2:37 PM Friedel-Crafts reaction: Mechanism: Carbocation is the reactive electrophile. AlCl4- picks up a proton. Limitations come from the mechanism: Carbocationic intermediates prone

More information

CHEM 211 CHAPTER 16 - Homework

CHEM 211 CHAPTER 16 - Homework CHEM 211 CHAPTER 16 - Homework SHORT ANSWER Consider the Friedel-Crafts alkylation reaction below to answer the following question(s): 1. Refer to the reaction above. Draw the structure of the electrophilic

More information

Electrophilic Aromatic Substitution

Electrophilic Aromatic Substitution Electrophilic Aromatic Substitution Electrophilic substitution is the typical reaction type for aromatic rings. Generalized electrophilic aromatic substitution: E E Electrophile Lewis acid: may be or neutral.

More information

REACTIONS OF AROMATIC COMPOUNDS

REACTIONS OF AROMATIC COMPOUNDS A STUDENT SHOULD BE ABLE TO: REACTIONS OF AROMATIC COMPOUNDS 1. Predict the product(s) of Electrophilic Aromatic Substitution (EAS), Nucleophilic Aromatic Substitution (S N Ar) and Elimination-Addition

More information

12.15 Multiple Substituent Effects

12.15 Multiple Substituent Effects 12.15 Multiple Substituent Effects The Simplest Case all possible EAS sites may be equivalent + CC AlCl 3 C 99% Another Straightforward Case Br 2 Br Fe N 2 N 2 86-90% directing effects of substituents

More information

Chapter 12 Electrophilic and Nucleophilic Aromatic Substitution

Chapter 12 Electrophilic and Nucleophilic Aromatic Substitution Chapter 12 Electrophilic and Nucleophilic Aromatic Substitution CHAPTER 12 Electrophilic and Nucleophilic Aromatic Substitution Aromatic compounds may undergo substitution reactions. Electrophilic aromatic

More information

Electrophilic Reactions on Aromatic Compounds Monosubstitution. Dr. Sapna Gupta

Electrophilic Reactions on Aromatic Compounds Monosubstitution. Dr. Sapna Gupta Electrophilic Reactions on Aromatic Compounds Monosubstitution Dr. Sapna Gupta Electrophilic Aromatic Substitution Arene (Ar-H) is the generic term for an aromatic hydrocarbon The aryl group (Ar) is derived

More information

Electrophilic Aromatic Substitution Part 1

Electrophilic Aromatic Substitution Part 1 Electrophilic Aromatic Substitution Part 1 Generic reaction: Optional reading: OCATSA Email instructor for access Introduction Fact: Alkenes undergo electrophilic addition Addition reaction: Increases

More information

Electrophilic Aromatic Substitution

Electrophilic Aromatic Substitution Electrophilic Aromatic Substitution Electrophilic Aromatic Substitution: a reaction in which the hydrogen atom of an aromatic ring is replaced as a result of an electrophilic attack on the aromatic ring

More information

CHEM 4113 ORGANIC CHEMISTRY II LECTURE NOTES CHAPTER 16

CHEM 4113 ORGANIC CHEMISTRY II LECTURE NOTES CHAPTER 16 M 4113 GI MISTY II LTU TS PT 16 1. romatic lectrophilic Substitution 1 romatic compounds are electron rich species ( 6 -electrons in the aromatic ring). onetheless, they do not undergo standard electrophilic

More information

12. Alcohols and Phenols. Based on McMurry s Organic Chemistry, 6 th edition

12. Alcohols and Phenols. Based on McMurry s Organic Chemistry, 6 th edition 12. Alcohols and Phenols Based on McMurry s Organic Chemistry, 6 th edition Alcohols and Phenols Alcohols contain an OH group connected to a saturated C (sp 3 ) They are important solvents and synthesis

More information

Reactions of Aromatic Compounds

Reactions of Aromatic Compounds c h a p t e r 15 eactions of Aromatic ompounds Although aromatic molecules have special electronic properties that render them inert to many standard reaction conditions, there are a number of ways to

More information

Suggested solutions for Chapter 21

Suggested solutions for Chapter 21 s for Chapter 21 21 PRBLEM 1 All you have to do is to spot the aromatic rings in these compounds. t may not be as easy as you think and you should give some reasons for questionable decisions. C 2 colchicine:

More information

Nucleophilic Aromatic Substitution (NAS) (Why do some aryl halides undergo NAS reactions while others do not?)

Nucleophilic Aromatic Substitution (NAS) (Why do some aryl halides undergo NAS reactions while others do not?) ChemActivity 39 leophilic Aromatic Substitution (NAS) 1 ChemActivity 39 leophilic Aromatic Substitution (NAS) (Why do some aryl halides undergo NAS reactions while others do not?) Review: leophilic Addition-Elimination

More information

Chapter 12 Reactions of Arenes: Electrophilic Aromatic Substitution. E δ+ δ

Chapter 12 Reactions of Arenes: Electrophilic Aromatic Substitution. E δ+ δ Chapter 12 Reactions of Arenes: Electrophilic Aromatic Substitution E δ δ E Y Y 12.1 Representative Electrophilic Aromatic Substitution Reactions of Benzene E δ δ E Y Y E δ δ E Y Y Electrophilic aromatic

More information

Reaction Coordinate Diagrams for the Two Benzene Reactions

Reaction Coordinate Diagrams for the Two Benzene Reactions Electrophilic Addition vs. Substitution ( LEAVES!) Electrophilic Aromatic Substitution δ δ E E Y Y Reaction Coordinate Diagrams for the Two Benzene Reactions δ δ E E Y Y Electrophilic aromatic substitutions

More information

15 Reactions of Aromatic Compounds

15 Reactions of Aromatic Compounds 15 eactions of Aromatic ompounds Thyroxine Thyroxine (see the model above ) is an aromatic compound and a key hormone that raises metabolic rate. Low levels of thyroxine (hypothyroidism) can lead to obesity,

More information

Benzene and aromatic compounds (McMurry Ch. 15 & 16) The resonance hybrid model explains these properties of benzene:

Benzene and aromatic compounds (McMurry Ch. 15 & 16) The resonance hybrid model explains these properties of benzene: Benzene and aromatic compounds (McMurry Ch. 15 & 16) C 6 H 6 is an unusually stable molecule that does NOT react like alkenes do A model was proposed by Kekule in 1865: The resonance hybrid model explains

More information

The Order of the Reactions is Important Pearson Education, Inc.

The Order of the Reactions is Important Pearson Education, Inc. The Order of the Reactions is Important Designing a Synthesis The first alkyl group is added by Friedel Crafts reaction. A Friedel Crafts reaction will not work with a meta director on the ring, so the

More information

Aromaticity and Reactions of Benzene

Aromaticity and Reactions of Benzene Aromaticity and eactions of Benzene ark College Benzene is a unique molecule it is highly unsaturated with 6 carbons and 6 hydrogens, it is planar, and has a high degree of symmetry. These features explain

More information

Arene(Ar-H) is the generic term for an aromatic hydrocarbon

Arene(Ar-H) is the generic term for an aromatic hydrocarbon 4.8 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 from an arene Aromatic compounds undergo

More information

SN2 Reactions of Benzylic Halides

SN2 Reactions of Benzylic Halides SN2 Reactions of Benzylic Halides SN2 of benzylic halides is faster than allylic halides. How can this be explained if there is no carbocation intermediate? Slide 1 1 Allylic SN2 Faster: Two Arguments

More information

17.7 Friedel-Crafts Alkylation

17.7 Friedel-Crafts Alkylation 690 CAPTER 17 ARMATIC SUBSTITUTIN REACTINS PRBLEM 1713 Show the products of these reactions: S 3 a) 2 S 4 b) 2 S 4 c) 2 S 4 d) 2 S 4 177 Friedel-Crafts Alkylation Developed by C Friedel and J M Crafts,

More information

Q.1 Draw out some suitable structures which fit the molecular formula C 6 H 6

Q.1 Draw out some suitable structures which fit the molecular formula C 6 H 6 Aromatic compounds GE 1 BENZENE Structure Primary analysis revealed benzene had an... empirical formula of and a molecular formula of 6 6 Q.1 Draw out some suitable structures which fit the molecular formula

More information

Part A: Electrophilic Aromatic Substitution (What products are formed when a strong electrophile is added to benzene?)

Part A: Electrophilic Aromatic Substitution (What products are formed when a strong electrophile is added to benzene?) hemactivity 29 lectrophilic Aromatic Substitution 1 hemactivity 29 Part A: lectrophilic Aromatic Substitution (What products are formed when a strong electrophile is added to benzene?) Model 1: (review)

More information

Electrophilic Aromatic Substitution Reactions

Electrophilic Aromatic Substitution Reactions hemistry 2600 Lecture Notes hapter 12 Electrophilic Aromatic Subsitution Page 1 of 16 Electrophilic Aromatic Substitution eactions Benzene (discovered 1825 by a (Physical!) chemist, Michael Faraday) is

More information

CHEM 322 Organic Chemistry II - Professor Kathleen V. Kilway. CHAPTER 14 Substitution Reactions of Aromatic Compounds

CHEM 322 Organic Chemistry II - Professor Kathleen V. Kilway. CHAPTER 14 Substitution Reactions of Aromatic Compounds CHEM 322 Organic Chemistry II - Professor Kathleen V. Kilway "Organic Chemistry" by Maitland Jones, 4 th edition Chapter 14 Homework: 1, 2, 5, 7, 13, 19, 20, 23, 26, 27, 28, 30, 31, 34, 35, 36, 41, 46,

More information

Chemistry 2030 Survey of Organic Chemistry Fall Semester 2013 Dr. Rainer Glaser

Chemistry 2030 Survey of Organic Chemistry Fall Semester 2013 Dr. Rainer Glaser Chemistry 2030 Survey of Organic Chemistry Fall Semester 2013 Dr. Rainer Glaser Examination #2 Arenes, Electrophilic Aromatic Substitution, Stereochemistry, and Nucleophilic Substitution and Elimination.

More information

Aromatic Substitution Reactions

Aromatic Substitution Reactions ornback_ch17_671-738 12/15/04 6:42 PM Page 671 Aromatic Substitution Reactions C A P T E R 17 MASTERING RGANIC CEMISTRY Predicting the Products of Aromatic Substitution Reactions Understanding the Mechanisms

More information

Richard F. Daley and Sally J. Daley Organic. Chapter 18 Aromatic Substitution Reactions

Richard F. Daley and Sally J. Daley  Organic. Chapter 18 Aromatic Substitution Reactions Richard F. Daley and Sally J. Daley www.ochem4free.com rganic Chemistry Chapter 18 Aromatic Substitution Reactions 18.1 Mechanism of Aromatic Electrophilic Substitution 914 18.2 The itration of Benzene

More information

SPRINGFIELD TECHNICAL COMMUNITY COLLEGE ACADEMIC AFFAIRS

SPRINGFIELD TECHNICAL COMMUNITY COLLEGE ACADEMIC AFFAIRS SPRINGFIELD TECHNICAL COMMUNITY COLLEGE ACADEMIC AFFAIRS Course Number: CHEM 420 Department: Chemistry Course Title: Organic Chemistry 2 Semester: Spring Year: 2001 Objectives/ 1. To learn the various

More information

Amines H 3 C CH CH CH 3. ethylmethylamine. Nomenclature. 1 o : RNH 2, 2 o : RR'NH, 3 o : RR'R"N, 4 o (salt) RR'R"R'"N + R = alkyl or aryl

Amines H 3 C CH CH CH 3. ethylmethylamine. Nomenclature. 1 o : RNH 2, 2 o : RR'NH, 3 o : RR'RN, 4 o (salt) RR'RR'N + R = alkyl or aryl Amines omenclature 1 o : 2, 2 o : ', 3 o : '", 4 o (salt) '"'" + = alkyl or aryl For aliphatic amines name groups attached to ; use suffix -amine. 3 2 3 ethylmethylamine In complicated structures the prefix

More information

Protonation. favored H 3 O + R O O H

Protonation. favored H 3 O + R O O H arboxylic Acids arboxylic acids have one property that distinguishes them from most other organic compounds they re acidic. Now not as acidic as fuming sulfuric acid, but still pretty darned acidic. The

More information

Aromatic Compounds CHAPTER SUMMARY

Aromatic Compounds CHAPTER SUMMARY 6 Aromatic Compounds CHAPTER SUMMARY 6.1 Introduction to Aromatic Compounds Aromatic compounds are compounds that are similar to benzene in structure and chemical behavior. Benzene, C 6 H 6, is a cyclic

More information

Table 2.1. Physical and thermodynamic Properties of Toluene

Table 2.1. Physical and thermodynamic Properties of Toluene PROPERTIES Physical Properties: The physical and thermodynamic properties of toluene are summarized in Table 2.1. Vapor pressure data for toluene are summarized in Table 2.2. Toluene forms azeotropes with

More information

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Exam Name SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 1) Provide the major resonance structures of the intermediate sigma complex in the reaction

More information

Reactions of Nucleophiles and Bases. (b) at sp 2 centers (c) aromatic substitution

Reactions of Nucleophiles and Bases. (b) at sp 2 centers (c) aromatic substitution Chapter 3 Reactions of Nucleophiles and Bases 1) Nucleophilic substitution (a) at sp 3 2) Eliminations (a) E2 (b) Ei (b) at sp 2 centers (c) aromatic substitution 3) Nucleophilic addition to carbonyl compounds

More information

11.2: Kekulé and the Structure of Benzene Kekule benzene: two forms are in rapid equilibrium

11.2: Kekulé and the Structure of Benzene Kekule benzene: two forms are in rapid equilibrium Chapter 11: Arenes and Aromaticity 11.1: Benzene - C 6 6 11.2: Kekulé and the Structure of Benzene Kekule benzene: two forms are in rapid equilibrium 154 pm 134 pm All bonds are 140 pm (intermediate between

More information

1. (10 pts) Provide a proper IUPAC name for the following molecules: O 2 N. Give the structural formula for the following IUPAC names:

1. (10 pts) Provide a proper IUPAC name for the following molecules: O 2 N. Give the structural formula for the following IUPAC names: 1. (10 pts) Provide a proper IUPAC name for the following molecules: F 2 N Give the structural formula for the following IUPAC names: Para-bromo-nitro benzene 3-sec-butyl-1-heptyne 2. (10 pts) Label each

More information

7.1 Introduction to Substitution Reactions. 7.1 Introduction to Substitution Reactions. Reactions. 7.2 Alkyl Halides. Reactions

7.1 Introduction to Substitution Reactions. 7.1 Introduction to Substitution Reactions. Reactions. 7.2 Alkyl Halides. Reactions 7.1 Introduction to Substitution Reactions One group of atoms is replaced with another. Generic example: 7.1 Introduction to Substitution Reactions Which side do you think will be favored in the dynamic

More information

Many non-systematic names: Table 20.1

Many non-systematic names: Table 20.1 hapter 20: arboxylic Acids and itriles 20.1 aming arboxylic Acids (please read) In general, the same for alkanes; replace the terminal -e of the alkane name with -oic acid The carboxyl carbon atom is 1

More information

CHEM 343 Principles of Organic Chemistry II Summer Instructor: Paul J. Bracher. Exam # 1. Tuesday, July 8 th, :00 9:15 a.m.

CHEM 343 Principles of Organic Chemistry II Summer Instructor: Paul J. Bracher. Exam # 1. Tuesday, July 8 th, :00 9:15 a.m. CHEM 343 Principles of rganic Chemistry II Summer 2014 Exam # 1 Solutions Key Page 1 of 7 CHEM 343 Principles of rganic Chemistry II Summer 2014 Instructor: Paul J. Bracher Exam # 1 Tuesday, July 8 th,

More information

Nitration of Methyl Benzoate

Nitration of Methyl Benzoate Experiment 9 Nitration of Methyl Benzoate Objectives 1) To prepare methyl nitrobenzoate by electrophilic aromatic substitution reactions. 2) To demonstrate the regiochemistry of electrophilic aromatic

More information

Alcohols (R-OH) and Alkyl halides R-X (X = F, Cl, Br, I) Alcohols. Suffix:

Alcohols (R-OH) and Alkyl halides R-X (X = F, Cl, Br, I) Alcohols. Suffix: Alcohols (R-O) and Alkyl halides R-X (X = F, Cl,, I) Alcohols Alcohols contain a R-O functional group. Primary, secondary or tertiary? O O O Nomenclature: Suffix: numbering scheme: The number locating

More information

The hydrogen halides H-Cl, H-Br, and H-I undergo addition to carbon bonds to give alkyl halides.

The hydrogen halides H-Cl, H-Br, and H-I undergo addition to carbon bonds to give alkyl halides. VII. Reactions of Alkenes: Electrophilic Addition The most characteristic reaction of alkenes is an Electrophilic Addition Reaction. + X Y Examples: X X O 3 O + (cat.) O 2 l 2 2 O O B 3 or 9-BBN BR 2 2

More information

MCAT Organic Chemistry - Problem Drill 20: Mechanisms of Organic Reactions

MCAT Organic Chemistry - Problem Drill 20: Mechanisms of Organic Reactions MCAT rganic Chemistry - Problem Drill 20: Mechanisms of rganic Reactions Question No. 1 of 10 Question 1. What does the arrow shown indicate in a mechanism? Question #01 (A) Movement of a pair of electrons

More information

Conjugation is broken completely by the introduction of saturated (sp3) carbon:

Conjugation is broken completely by the introduction of saturated (sp3) carbon: Chapter 16 Conjugation, resonance, and dienes Conjugation relies on the partial overlap of p-orbitals on adjacent double or triple bonds. A common conjugated system involves 1,3-dienes, such as 1,3-butadiene.

More information

Electrophilic Addition Reactions

Electrophilic Addition Reactions Electrophilic Addition Reactions Electrophilic addition reactions are an important class of reactions that allow the interconversion of C=C and C C into a range of important functional groups. Conceptually,

More information

Carboxylic Acids When a carbonyl carbon also bears a hydroxyl group, then these compounds are appreciably acidic, and are called carboxylic acids.

Carboxylic Acids When a carbonyl carbon also bears a hydroxyl group, then these compounds are appreciably acidic, and are called carboxylic acids. Carboxylic Acids When a carbonyl carbon also bears a hydroxyl group, then these compounds are appreciably acidic, and are called carboxylic acids. R Carboxylic acids are classified according to the substituent

More information

Carbon-Carbon Bond Forming Reactions

Carbon-Carbon Bond Forming Reactions Carbon-Carbon Bond Forming eactions Addition of Cyanide Nucleophiles S N 2 displacement N 2 X KCN CN C - X = I, Br, Cl, Ts, Ms - SN2 process reactivity? stereochemistry? - one carbon chain extension addition

More information

AROMATIC COMPOUNDS A STUDENT SHOULD BE ABLE TO:

AROMATIC COMPOUNDS A STUDENT SHOULD BE ABLE TO: A STUDENT SHOULD BE ABLE TO: AROMATIC COMPOUNDS 1. Name benzene derivatives given the structures, and draw the structures given the names. This includes: Monosubstituted benzenes named as derivatives of

More information

Basic Organic Chemistry

Basic Organic Chemistry Reactions of Aromatic Compounds Basic rganic Chemistry 2302202 Dr Rick Attrill ffice MMK 1405/5 lectrophilic Aromatic Substitution Reactions Mechanism alogenation Nitration Sulfonation Friedel Crafts Alkylation

More information

Retrosynthetic Disconnections

Retrosynthetic Disconnections 1 Retrosynthetic Disconnections These notes should help somewhat when planning a synthesis. Recall that retrosynthetic analysis is the method used to work backwards from the target molecule to the starting

More information

350 o C + high P. + NaOH H 2 O. + Br 2, FeBr 3. from Meisenheimer. + Br 2 NBS. O AlCl 3 + H 3 C. CHM238 Fall 2002 Practice Exam 2

350 o C + high P. + NaOH H 2 O. + Br 2, FeBr 3. from Meisenheimer. + Br 2 NBS. O AlCl 3 + H 3 C. CHM238 Fall 2002 Practice Exam 2 M238 Fall 2002 Practice Exam 2 1. omplete 5 out of the 6 following reactions, showing the main organic products. ross one out or graded in order. Al 3 3 + 3 (a) Friedel-rafts Acylation, is o,p director

More information

Chemistry of Carbonyl Compounds

Chemistry of Carbonyl Compounds Chemistry of Carbonyl Compounds ucleophilic addition (1,2-add) / substitution Conjugate addition (1,4 add) obinson annulation Alkylation of enolate anions namines as enolate equivs. alogenation of enols

More information

Chemistry Notes for class 12 Chapter 13 Amines

Chemistry Notes for class 12 Chapter 13 Amines 1 P a g e Chemistry Notes for class 12 Chapter 13 Amines Amines constitute an important class of organic compounds derived by replacing one or more hydrogen atoms ofnh 3 molecule by alkyl/aryl group(s).

More information

CHEM 341: Organic Chemistry I

CHEM 341: Organic Chemistry I EM 341: rganic hemistry I at North Dakota tate University Final Exam - tudy Guide Reactions to know ubstitution of Alcohols R X R X N 1 ubstitution - N 2 ubstitution 3 carbocation best 2 carbocation ok

More information

Sn1 REACTINS From a synthetic point of view, the Sn1 reaction is less useful. It is prone to side reactions such as eliminations and carbocation rearr

Sn1 REACTINS From a synthetic point of view, the Sn1 reaction is less useful. It is prone to side reactions such as eliminations and carbocation rearr IGLIGTS F NUCLEPILIC SUBSTITUTIN REACTINS INVLVING sp3 CARBN Nu + C L C Nu + L Nucleophile Electrophile, or substrate L= leaving group Nucleophilic substitution product Sn2 REACTINS From a synthetic point

More information

Chapter 8. Alcohols, Phenols, and Ethers

Chapter 8. Alcohols, Phenols, and Ethers Chapter 8. Alcohols, Phenols, and Ethers Alcohol: A compound that has a hydroxyl group ( ) bonded to a saturated, sp 3 - hybridized carbon atom. Phenol: A compound that has a hydroxyl group bonded to an

More information

Nomenclature of substituted benzene rings

Nomenclature of substituted benzene rings Chem 263 ct. 5, 2010 Nomenclature of substituted benzene rings When you have two substituents on a benzene ring, ortho, meta, and para are used to tell where the second substitution is relative to the

More information

Chapter 14 Substituent Effects

Chapter 14 Substituent Effects Chapter 14 Substituent Effects from Organic Chemistry by Robert C. Neuman, Jr. Professor of Chemistry, emeritus University of California, Riverside orgchembyneuman@yahoo.com

More information

ammonium salt (acidic)

ammonium salt (acidic) Chem 360 Jasperse Ch. 19 otes. Amines 1 eactions of Amines 1. eaction as a proton base (Section 19-5 and 19-6) amine base -X (proton acid) a X ammonium salt (acidic) Mechanism: equired (protonation) everse

More information

6.1.1 Aromatic Compounds

6.1.1 Aromatic Compounds 6.1.1 Aromatic ompounds There are two major classes of organic chemicals aliphatic : straight or branched chain organic substances aromatic or arene: includes one or more ring of six carbon ams with delocalised

More information

Chapter 11. Free Radical Reactions

Chapter 11. Free Radical Reactions hapter 11 Free Radical Reactions A free radical is a species containing one or more unpaired electrons Free radicals are electron-deficient species, but they are usually uncharged, so their chemistry is

More information

CHEMISTRY 263 Module7. Hydrogenation of Alkenes Text Sections: Homework Chapter7: Module8. Alkenes and Alkynes II: Addition reactions

CHEMISTRY 263 Module7. Hydrogenation of Alkenes Text Sections: Homework Chapter7: Module8. Alkenes and Alkynes II: Addition reactions 1 CHEMISTRY 263 Module7. Hydrogenation of Alkenes The Function of the Catalyst - Syn and anti- addition Hydrogenation of Alkynes - Syn- addition of hydrogen: Synthesis of cis-alkenes - Anti addition of

More information

13 Friedel-Crafts Acylation of Anisole

13 Friedel-Crafts Acylation of Anisole 13 Friedel-Crafts Acylation of Anisole 13.1 Introduction A benzene ring is rich in -electrons, making it susceptible to electrophilic aromatic substitution (EAS) reactions. These reactions proceed by initial

More information

AROMATIC COMPOUNDS A STUDENT SHOULD BE ABLE TO:

AROMATIC COMPOUNDS A STUDENT SHOULD BE ABLE TO: A STUDENT SHULD BE ABLE T: ARMATIC CMPUNDS 1. Name benzene derivatives given the structures, and draw the structures given the names. This includes: Monosubstituted benzenes named as derivatives of benzene:

More information

Chapter 13. Conjugated Unsaturated Systems. Conjugation, Resonance and Dienes. Conjugation, Resonance and Dienes. What is the conjugation?

Chapter 13. Conjugated Unsaturated Systems. Conjugation, Resonance and Dienes. Conjugation, Resonance and Dienes. What is the conjugation? Chapter 13 Conjugation, Resonance and Dienes What is the conjugation? Conjugation occurs whenever p orbitals are located on three or more adjacent atoms. Conjugated Unsaturated Systems The four p orbitals

More information

Chapter 9 Alkynes. Alkynes are hydrocarbons that contain a carbon-carbon triple bond. They have the formula C n H 2n-2. C C CH 3

Chapter 9 Alkynes. Alkynes are hydrocarbons that contain a carbon-carbon triple bond. They have the formula C n H 2n-2. C C CH 3 . 9 hapter 9 Alkynes Alkynes are hydrocarbons that contain a carbon-carbon triple bond. They have the formula n 2n-2. Nomenclature: The parent is the longest chain that contains the triple bond. hange

More information

Learning Guide for Chapter 8 - Organic Reactions II

Learning Guide for Chapter 8 - Organic Reactions II Learning Guide for hapter 8 - rganic Reactions II I. Substitution, Addition, and Elimination Reactions II. xidation and Reduction Reactions III. Radical Reactions IV. Reactive Intermediates V. Stereochemistry

More information

Chapter 15 Radical Reactions. Radicals are reactive species with a single unpaired electron, formed by

Chapter 15 Radical Reactions. Radicals are reactive species with a single unpaired electron, formed by Chapter 15 Radical Reactions Radicals are reactive species with a single unpaired electron, formed by homolysis of a covalent bond; a radical contains an atom that does not have an octet of electrons,

More information

CHM 221: Organic Chemistry II Review for Exam 1 Answers Electrophilic Addition Reactions

CHM 221: Organic Chemistry II Review for Exam 1 Answers Electrophilic Addition Reactions CM 221: rganic Chemistry II Review for Exam 1 Answers Electrophilic Addition Reactions 1. Draw the structure of the carbocation intermediate and the major reaction product for each of the following reactions.

More information