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MARCH’S ADVANCED ORGANIC CHEMISTRY

MARCH’S ADVANCED

ORGANIC CHEMISTRY

REACTIONS, MECHANISMS, AND STRUCTURE

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Library of Congress Cataloging-in-Publication Data

Names: Smith, Michael, 1946 October 17- author | March, Jerry, 1929–1997.

Title: March’s advanced organic chemistry : reactions, mechanisms, and structure.

Other titles: Advanced organic chemistry

Description: Eighth edition / Michael B Smith (University of Connecticut, Department of Chemistry) | Hoboken, NJ : John Wiley & Sons, Inc., 2020 | Includes index.

Identifiers: LCCN 2019023265 (print) | LCCN 2019023266 (ebook) | ISBN 9781119371809 (cloth) | ISBN

9781119371786 (adobe pdf) | ISBN 9781119371793 (epub)

Subjects: LCSH: Chemistry, Organic.

Classification: LCC QD251.2 M37 2020 (print) | LCC QD251.2 (ebook) | DDC 547—dc23

LC record available at https://lccn.loc.gov/2019023265

LC ebook record available at https://lccn.loc.gov/2019023266

Cover image: Background © atakan/iStock.com, All other images courtesy of Michael B Smith

Cover design by Wiley

Set in 10/12pt TimesLTStd by Aptara Inc., New Delhi, India

2.B Bond Energies and Distances in Compounds Containing

2.G Steric Inhibition of Resonance and the Influences of Strain 48

v

vi CONTENTS

2.I.iii Other Systems Containing Aromatic Sextets 67

2.K Aromatic Systems with Electron Numbers Other Than Six 70

2.K.ii Systems of Four Electrons: Antiaromaticity 73

2.K.v Systems of More than Ten Electrons: 4n + 2 Electrons 802.K.vi Systems of More Than Ten Electrons: 4n Electrons 85

4.B Dependence of Rotation on Conditions of Measurement 1354.C What Kinds of Molecules Display Optical Activity? 136

CONTENTS vii

4.M Enantiotopic and Diastereotopic Atoms, Groups, and Faces 183

4.O.iii Conformation in Six-Membered Rings Containing

5 Carbocations, Carbanions, Free Radicals, Carbenes, and Nitrenes 223

5.A.iii The Generation And Fate Of Carbocations 234

5.B.ii The Structure Of Organometallic Compounds 244

5.C.ii The Generation and Fate of Free Radicals 261

viii CONTENTS

6.J.ii Determination of the Presence of an Intermediate 294

7 Irradiation Processes and Techniques that Influence Reactions in

7.A.ii Singlet and Triplet States: “Forbidden” Transitions 316

7.A.iv Nomenclature and Properties of Excited States 318

7.A.vi The Fate of the Excited Molecule: Physical Processes 3207.A.vii The Fate of the Excited Molecule: Chemical Processes 3257.A.viii The Determination of Photochemical Mechanisms 330

8.F The Effects of Structure on the Strengths of Acids and Bases 3618.G The Effects of the Medium on Acid and Base Strength 370

9.C Quantitative Treatments of the Effect of Structure on Reactivity 380

10.C.i Neighboring-Group Participation by π and σ Bonds:

10.G.ii The Effect of the Attacking Nucleophile 457

11.B.i Orientation and Reactivity in Monosubstituted Benzene

x CONTENTS

11.B.iv Orientation in Benzene Rings With More Than One

11.C Quantitative Treatments of Reactivity in the Substrate 62411.D A Quantitative Treatment of Reactivity of the Electrophile: The

12 Aliphatic, Alkenyl, and Alkynyl Substitution: Electrophilic and

12.A.iii Electrophilic Substitution Accompanied by Double-Bond

13 Aromatic Substitution: Nucleophilic and Organometallic 767

13.B.iii The Effect of the Attacking Nucleophile 779

13.C.i All Leaving Groups Except Hydrogen And N2+ 779

14.A.iv Neighboring-Group Assistance in Free-Radical Reactions 847

15.C.i Isomerization of Double and Triple Bonds 90815.C.ii Reactions in Which Hydrogen Adds to One Side 91015.C.iii Reactions in Which Hydrogen Adds to Neither Side 992

16.A.i Nucleophilic Substitution at an Aliphatic Trigonal Carbon:

xii CONTENTS

16.B.i Reactions in Which Hydrogen or a Metallic Ion Adds

16.B.iii Reactions in Which Carbon Adds to the Heteroatom 1257

16.B.v Nucleophilic Substitution at a Sulfonyl Sulfur Atom 1266

17.E Mechanisms and Orientation in Pyrolytic Eliminations 1295

CONTENTS xiii

APPENDIX B: CLASSIFICATION OF REACTIONS BY TYPE OF

INDEXES

NEW REACTION SECTIONS CORRELATION: 7TH

xvi NEW REACTION SECTIONS CORRELATION: 7TH EDITION → 8TH EDITION

NEW REACTION SECTIONS CORRELATION: 7TH EDITION → 8TH EDITION xvii

xviii NEW REACTION SECTIONS CORRELATION: 7TH EDITION → 8TH EDITION

NEW REACTION SECTIONS CORRELATION: 7TH EDITION → 8TH EDITION xix

This eighth edition of March’s Advanced Organic Chemistry has been thoroughly updated

to include new advances in areas of organic chemistry published between 2011 and 2017.Every topic retained from the seventh edition has been brought up to date if there wasactivity in that area during that six-year period Changes also include a significant rewrite

of most of the book More than 5800 new references have been added for work publishedsince 2011 As with the seventh edition, many older references were deleted to make roomfor new ones In cases where a series of papers by the same principal author were cited, mostbut the most recent were deleted Be aware that the older citations can usually be found byreferring to the more recent publications It is noted that more than 250 000 articles for theyears 2011–2017, from 31 journals, were scanned for this edition Of this huge number ofarticles, just over 8000 were examined in detail for inclusion in this work, with 5853 finallychosen With such numbers, it is inevitable that some work was not included, and it wasimpossible to include representative research in many areas For example, over 2000 of the

8000 articles examined were relevant to the transition metal-catalyzed reactions covered

in reactions 13-3 to 13-13 It was simply impossible to keep a representative number of

articles for this subject area There were other areas of research that were also too extensivefor complete inclusion of all references

Many of the reaction drawings considered to be redundant or not very useful were deletedwhen compiling the eighth edition A few new sections of text were added to better reflectsome areas of research Several of the older sections were moved to new chapters, espe-cially the ones that deal with hydrogenation of alkenes and alkynes; as these are clearlyreductions they were moved to Chapter 19 Some sections were combined with others andthe original section deleted These actions required renumbering the sections for the eighthedition A correlation table of the sections in the seventh edition and their placement in theeighth edition is provided below However, the fundamental structure of the eighth edition

is essentially the same as that of all previous editions

The goal, as in previous editions, is to give equal weight to three fundamental aspects

of the study of organic chemistry: reactions, mechanisms, and structure References areprovided, and every effort has been given to provide a snapshot of current research.Specific but specialized areas of organic chemistry—terpenes, carbohydrates, proteins,many organometallic reagents, combinatorial chemistry, polymerization and electrochem-ical reactions, steroids, etc.—have been incorporated into a great many pertinent sectionsrather than segregated into their own sections

This book is largely directed at graduate students in their first year of study and to graduates advanced in their studies, but previous editions have, for many years, been used

under-as an off-the-shelf reference book This practice should continue with the eighth edition It

is hoped that this book will lead a student to consult the many excellent books and reviewarticles cited for various topics in order to understand the subject in more detail Indeed,most of these topics are so vast they cannot be explained completely in this book

xxi

xxii PREFACE

The structure of organic compounds is discussed in Chapters 1–5 (found in Part I); thesechapters provide the background that is necessary for understanding mechanisms, but areimportant in their own right The discussion begins with chemical bonding (Chapter 1) andends with a chapter on stereochemistry (Chapter 4) Chapter 5 discusses the structure ofintermediates Chapters 6 and 7 then address reaction mechanisms in general, Chapter 6for ordinary reactions and Chapter 7 for photochemical reactions Other methods related toreactions are included in Chapter 7, including microwave chemistry, the use of ultrasound,mechanochemistry, and the relatively new area of reactions done under flow conditions.Part I concludes with Chapters 8 and 9, which give further background to the study ofmechanisms and reaction conditions

The Introduction to Part II briefly describes how the second part of the book is nized The organization is based on reaction types, and a relatively few principles suffice

orga-to explain nearly all the types, despite the large number of organic reactions Accordingly,the reactions and mechanisms section of this book (Part II) is divided into ten chapters,each being concerned with a different type of reaction In the first part of each chapter theappropriate basic mechanisms are discussed, along with considerations of reactivity andorientation The second part of each chapter is devoted to individual reaction types, wherethe scope and the mechanism of each reaction are discussed Numbered sections are used forthe reactions and theses are set in boldface when given as cross-references Since the meth-ods for the preparation of individual classes of compounds (e.g., ketones, nitriles, etc.) arenot treated all in one place, an updated and revised index has been provided (Appendix B)

by use of which the synthesis of a given type of compound may be found

It is important to note that the reaction numbers (e.g., 10-25) for many reactions in the

eighth edition are different from those in the sixth and seventh editions A table is included

that precedes this Preface that directly correlates the reaction numbers found in the eighthedition with the reaction numbers that were used in the sixth and seventh editions Note alsothat changes in the sixth edition made the reaction numbers from editions 1–5 different inmany cases to those in the sixth edition To see the differences between the fifth and sixtheditions, the reader is referred to the sixth edition

Although IUPAC has published a system for designating reaction mechanisms, the ignations for reactions that were featured in editions 1–7 have been removed, in large partbecause they are not extensively used and in part because many reactions were deemed bythis author as difficult to categorize using only one designation

des-In treating subjects as broad as structure, reactions, and mechanisms of organic istry, it is impossible to cover each topic in great depth, though this would not be desirableeven if possible This book is intended to point the reader to the primary literature (theoriginal journal publications) Secondary literatures sources, including reviews, books, andmonographs, have also been included

chem-Appendix A provides a brief introduction to using modern computer-based search

engines such as Reaxys®and SciFinder®

Although basically designed as a reference text for a one-year course at graduate level,this book can also be used in advanced undergraduate courses but is most useful after com-pletion of a one-year course in organic chemistry It has been my experience that studentswho have completed the first-year courses often have a hazy recollection of the material andgreatly profit from a re-presentation of the material if it is easily accessible The material inthe first nine chapters, particularly chapters 1, 2, 4, 6, and 8, may be helpful for reviewingsuch material when this book is used in connection with a course

PREFACE xxiii

This book is probably most valuable as a reasonably up-to-date reference work Bothstudents preparing for qualifying examinations and practicing organic chemists will findthat Part II contains a survey of the mechanism and scope of a large number of reactions,arranged in an orderly manner based on reaction type and on which bonds are broken andformed

IUPAC mandates joules for units of energy, but many journals do not use this unit sively Indeed, organic chemists who publish in United States’ journals commonly use calo-ries Virtually all energy values are presented here in both calories and joules

exclu-Although IUPAC does not recommend angstrom units ( ˚A) for bond distances, preferringinstead picometers (pm), a vast number of bond distances published in the literature are inangstrom units, and this book therefore uses angstrom units

I would like to acknowledge the contributions of those chemists cited and thanked byProfessor March in the first four editions, and those I thanked in the fifth, sixth, and seventheditions This book would not be possible without their contributions I thank the manypeople who have contributed comments or have pointed out errors in editions 5–7 that wereinvaluable to putting together this edition I thank Warren Hehre and Sean Ohlinger of

(v 1.0.1), allowing the incorporation of Spartan models for selected molecules and diates All structures and line drawings in this book were done using ChemDraw®Profes-sional 15.1.0.144 (2348350), graciously provided by PerkinElmer Corporation, Waltham,MA

interme-Special thanks are due to the Interscience division of John Wiley & Sons and to StefanieVolk and to Jonathan Rose, and also to Katrina Maceda at Wiley for their fine work aseditors in turning the manuscript into the finished book I also thank Tim Jackson for anexcellent job of copy editing the manuscript

With gratitude, I acknowledge the work of the late Jerry March, upon whose work all theeditions I have authored is built, although updates and changes have been made, beginningwith the fifth edition, However, Jerry is responsible for the concept and fundamental orga-nization of this book and he carried it through four very successful editions I used Jerry’sbook as a student and it is an honor to continue this tradition

I encourage those who read and use the eight edition to contact me directly with ments and errors and with publications that might be appropriate for future editions I hopethat this new edition will do justice to the tradition that Professor March began nearly

com-60 years ago

Finally, I want to thank my wife Sarah for her patience and understanding during thepreparation of this manuscript I also thank my son Steven Without them, this work wouldnot have been possible

Michael B Smith

Professor Emeritus October, 2018

sodium salt

xxv

xxvi COMMON ABBREVIATIONS

CIDNP chemical induced dynamic polarization

cod ligand 1,5-cyclooctadienyl

cot ligand 1,3,5-cyclooctatrienyl

dba ligand dibenzylidene acetone

COMMON ABBREVIATIONS xxvii

1H NMR proton nuclear magnetic resonance

(spectroscopy)

HOMO highest occupied molecular orbital

chromatography

IUPAC International Union of Pure and Applied

ChemistryLCAO linear combination of atomic orbitals

LICA (LIPCA) lithium N-isopropyl-N-cyclohexylamide

LTMP lithium 2,2,6,6-tetramethylpiperidide

NOESY nuclear Overhauser effect spectroscopy

chloride)

xxviii COMMON ABBREVIATIONS

Oxone® 2 KHSO5∙KHSO4∙K2SO4

Red-Al [(MeOCH2CH2O)2AlH2]Na

salen ligand N,N′-ethylenebis(salicylimine)

scCO2 supercritical carbon dioxide

(Sia)2BH disiamylborane (siamyl is sec-isoamyl)

TEMPO 2,2,6,6-tetramethylpiperidine-1-oxyl

free radical

ThexBH2 thexylborane (tert-hexylborane)

COMMON ABBREVIATIONS xxix

TOSMIC toluenesulfonylmethyl isocyanide

BIOGRAPHICAL STATEMENT

I was born in Detroit, Michigan, and moved to Madison Heights, Virginia, in 1957 I uated from Amherst County High School in 1964 I worked at Old Dominion Box Factoryfor a year and then started college at Ferrum Jr College in 1965 I graduated in 1967 with anA.A and began studies at Virginia Tech later that year, graduating with a B.S in Chemistry

grad-in 1969 I worked as a chemist at the Newport News Shipbuildgrad-ing & Dry Dock Co., NewportNews, Virginia, from 1969 until 1972 In 1972 I began studies in graduate school at PurdueUniversity, West Lafayette, Indiana, working with Prof Joseph Wolinsky I graduated in

1977 with a Ph.D in Organic Chemistry I took a postdoctoral position at Arizona StateUniversity in Tempe, Arizona, working on the isolation of anti-cancer agents from marineanimals with Prof Bob Pettit After one year, I took another postdoctoral position at MIT

in Cambridge, Massachusetts, working on the synthesis of the anti-cancer drug bleomycinwith Prof Sidney Hecht

I began my independent career as a assistant professor in the Chemistry department atthe University of Connecticut (UCONN), Storrs, CT, in 1979 I received tenure in 1986,and spent six months on sabbatical in Belgium with Prof Leon Ghosez at the Universit´eCatholique de Louvain in Louvain la Neuve, Belgium I was promoted to full professor

in 1994 and have spent my entire career at UCONN My research involved the synthesis

of biologically interesting molecules My most recent work involved the preparation offunctionalized indocyanine dyes for the detection of hypoxic cancerous tumors (breastcancer), and also the synthesis of inflammatory lipids derived from the dental pathogen,

Porphyromonas gingivalis I have published 25 books and published 95 peer-reviewed

research articles I retired from UCONN in January 2017

xxxi

NEW FEATURES OF THE 8THEDITION

r The book has been extensively rewritten.

2017, and about 85–90% of all citations in the book taken from literature since 2000

sections combined with existing sections and replaced with new sections

r Spartan molecular models continue to be included for selected molecules and

interme-diates and to replace arcane drawings of molecular orbitals wherever possible

r Appendix B, which correlates reaction type with section numbers, has been completely

revised and updated

r A correlation table for conversion of reaction sections in the 8th edition to those that

previously appeared in the 6th and 7th editions is included in the Preface

xxxiii

PART I

INTRODUCTION

This book contains 19 chapters Chapters 1 to 9 may be thought of as an introduction toPart II The first five chapters deal with the structure of organic compounds These chaptersdiscuss the kinds of bonding important in organic chemistry, the fundamental principles

of conformation and stereochemistry of organic molecules, and reactive intermediates inorganic chemistry Chapters 6 to 9 are concerned with general principles of mechanism

in organic chemistry, including acids and bases, photochemistry, sonochemistry andmicrowave irradiation, and finally the relationship between structure and reactivity.Chapters 10 to 19, which make up Part II, are directly concerned with the nature and thescope of organic reactions and their mechanisms

March’s Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, Eighth Edition Michael B Smith.

© 2020 John Wiley & Sons, Inc Published 2020 by John Wiley & Sons, Inc.

1

CHAPTER 1

Localized Chemical Bonding

Localized chemical bonding may be defined as bonding in which the electrons are shared by

two and only two nuclei Such bonding is the essential feature associated with the structure

of organic molecules.1Chapter 2 will discuss delocalized bonding, in which electrons are

shared by more than two nuclei

1.A COVALENT BONDING 2

Wave mechanics is based on the fundamental principle that electrons behave as waves (e.g.,they can be diffracted) Consequently, a wave equation can be written for electrons, in thesame sense that light waves, sound waves, and so on can be described by wave equations

The equation that serves as a mathematical model for electrons is known as the Schr¨odinger

equation, which for a one-electron system is:

where m is the mass of the electron, E is its total energy, V is its potential energy, and

h is Planck’s constant In physical terms, the function Ψ expresses the square root of the

probability of finding the electron at any position defined by the coordinates x, y, and z,

where the origin is at the nucleus The equation is similar, but more complicated, for systemscontaining more than one electron

The Schr¨odinger equation is a differential equation, so solutions to it are themselvesequations; however, the solutions are not differential equations but simple equations forwhich graphs can be drawn Such graphs are essentially three-dimensional (3D) pictures

1See Hoffmann, R.; Schleyer, P.v.R.; Schaefer III, H.F Angew Chem Int Ed 2008, 47, 7164.

2 This treatment of orbitals is simplified by necessity For more detailed treatments of orbital theory, as applied

to organic chemistry, see Matthews, P.S.C Quantum Chemistry of Atoms and Molecules, Cambridge University

Press, Cambridge, 1986; Clark, T A Handbook of Computational Chemistry, Wiley, NY, 1985; Albright, T.A.; Burdett, J.K.; Whangbo, M Orbital Interactions in Chemistry, Wiley, NY, 1985; MacWeeny, R.M Coulson’s Valence, Oxford University Press, Oxford, 1980; Murrell, J.N.; Kettle, S.F.A; Tedder, J.M The Chemical Bond, Wiley, NY, 1978; Dewar, M.J.S.; Dougherty R.C The PMO Theory of Organic Chemistry, Plenum, NY, 1975; Zimmerman, H.E Quantum Mechanics for Organic Chemists, Academic Press, NY, 1975; Borden, W.T Modern Molecular Orbital Theory for Organic Chemists, Prentice-Hall, Englewood Cliffs, NJ, 1975.

March’s Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, Eighth Edition Michael B Smith.

© 2020 John Wiley & Sons, Inc Published 2020 by John Wiley & Sons, Inc.

3

4 LOCALIZED CHEMICAL BONDING

–

–

FIGURE 1.1 (a) The 1s orbital (b) The three degenerate 2p orbitals.

that show the electron density, and these pictures are representations of orbitals, which are electron clouds Most students are familiar with the shapes of the s and p atomic orbitals

(Figure 1.1).3Note that each p orbital has a node: a region in space where the probability

of finding the electron is extremely small.4Also note that in Figure 1.1 some lobes of theorbitals are labeled (+) and others (−) These signs do not refer to positive or negative

charges, since both lobes of an electron cloud must be negatively charged, but rather refer

to the signs of the wave function Ψ When a node separates two parts of an orbital, a point ofzero electron density, Ψ, always has opposite signs on the two sides of the node According

to the Pauli exclusion principle, no more than two electrons can be present in any orbital,

and they must have opposite spins

Unfortunately, the Schr¨odinger equation can be solved exactly only for one-electron tems, such as the hydrogen atom If it could be solved exactly for molecules containing two

sys-or msys-ore electrons,5a precise picture of the shape of the orbitals available to each electron(especially for the important ground state) would become available, as well as the energy foreach orbital Since exact solutions are not available, drastic approximations must be made.There are two chief general methods of approximation: the molecular-orbital method andthe valence-bond method

In the molecular-orbital method, bonding is considered to arise from the overlap ofatomic orbitals When any number of atomic orbitals overlap, they combine to form an

equal number of new orbitals, called molecular orbitals Molecular orbitals differ from

atomic orbitals in that an electron cloud effectively surrounds the nuclei of two or moreatoms, rather than just one atom In other words, the electrons are shared by more than one

3 The argument has been proposed that hybrid atomic orbitals should not be taught in a chemistry curriculum See

Grushow, A J Chem Educ 2011, 88, 860.

4 When wave-mechanical calculations are made according to the Schr¨odinger equation, the probability of finding the electron in a node is zero, but this treatment ignores relativistic considerations When such considerations are

applied, Dirac has shown that nodes do have a very small electron density: Powell, R.E J Chem Educ 1968, 45,

558 See also, Ellison, F.O.; Hollingsworth, C.A J Chem Educ 1976, 53, 767; McKelvey, D.R J Chem Educ.

1983, 60, 112; Nelson, P.G J Chem Educ 1990, 67, 643 For a general review of relativistic effects on chemical structures, see Pyykk¨o, P Chem Rev 1988, 88, 563.

5See Roothaan, C.C.J.; Weiss, A.W Rev Mod Phys 1960, 32, 194; Kolos, W.; Roothaan, C.C.J Rev Mod Phys.

1960, 32, 219 See Clark, R.G.; Stewart, E.T Q Rev Chem Soc 1970, 24, 95.

COVALENT BONDING 5 σ* (antibonding orbital)

FIGURE 1.2 Overlap of two 1s orbitals gives rise to a σ orbital and a σ* orbital.

atom rather than being localized on a single atom In localized bonding for a single lent bond, the number of atomic orbitals that overlap is two (each containing one electron),

cova-so that two molecular orbitals are generated One of these, called a bonding orbital, has a

lower energy than the original atomic orbitals, otherwise a bond would not form, and the

other, called an antibonding orbital, has a higher energy Orbitals of lower energy fill first.

Since the two original atomic orbitals each held one electron, both of these electrons will

reside in the new molecular bonding orbital, which is lower in energy Remember that any

orbital can hold only two electrons The higher energy antibonding orbital remains empty

in the ground state

The strength of a bond is determined by the amount of electron density that residesbetween the two nuclei The greater the overlap of the orbitals, the stronger the bond, buttotal overlap is prevented by repulsion between the nuclei Determining the electron den-sity at the carbon atom, although difficult, is important for the stability of a molecule Onemethod to determine this parameter is quantum theory using the atomic charges and vol-umes of carbon atoms,6as these are good descriptors of electron depletion and are indicative

of the stability and reactivity of a molecule

Figure 1.2 shows the bonding and antibonding orbitals that arise by the overlap of two

1s electrons Note that since the antibonding orbital has a node between the nuclei, there is

practically no electron density in that area, so that this orbital cannot be expected to bondvery well When the centers of electron density are on the axis common to the two nuclei, the

molecular orbitals formed by the overlap of two atomic orbitals are called σ (sigma) orbitals,

and the bonds are called σ bonds The corresponding antibonding orbitals are designated

σ* Sigma orbitals may be formed by the overlap of any of the atomic orbitals (s, p, d, or f), whether the same or different, not only by the overlap of two s orbitals However, the two lobes that overlap must have the same sign: a positive s orbital can form a bond only by

6Krˇzan, A.; Mavri, J J Org Chem 2011, 76, 1891.