Leeuwen Homogeneous Catalysis

Understanding the Art
1. Auflage 2006
ISBN: 978-1-4020-2000-1
Verlag: Springer Netherlands
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 433 Seiten

Homogeneous Catalysis: Understanding the Art gives real insight in the many new and old reactions of importance. It is based on the author's extensive experience in both teaching and industrial practice. Each chapter starts with the basic knowledge and ends with up-to-date concepts. The focus of this book is on concepts, but many key industrial processes and applications that are important in the laboratory synthesis of organic chemicals are used as examples. The full range of topics is covered, such as fine chemicals, bulk chemicals, polymers, high-tech polymers, pharmaceuticals, but also important techniques and reaction types among other aspects. For a few reactions the process schemes, environmental concerns and safety aspects are included, to encourage catalyst researchers to think about these topics at an early stage of their projects and to communicate with chemical engineers, customers and the end-users.

Homogeneous Catalysis: Understanding the Art provides a balanced overview of the vibrant and growing field of homogeneous catalysis to chemists trained in different disciplines and to graduate students who take catalysis as a main or secondary subject. This book is an invaluable tool for practising professionals and academia, including: Chemists in academia with an inorganic, organic, catalytic, etc., chemistry background, PhD-students in these fields, and advanced students,Research Institutes of Petrochemical industries, Fine-chemical industries, Pharmaceutical industries, Chemical Laboratories of Universities for Organic, Industrial, Inorganic, and Physical Chemistry, and Catalysis, Graduate schools. There is no other book available that gives insight into so many reactions of importance, while the field of homogeneous catalysis is becoming more and more important to organic chemists, industrial chemists, and academia. This book will provide this background to chemists trained in a different discipline and graduate and masters students who take catalysis as a main or secondary topic.

Written for:
Chemists trained in a different discipline and graduate and masters students who take catalysis as a main or secondary topic

Autoren/Hrsg.

Leeuwen, Piet W. N. M. van

Inhaltsverzeichnis

1;Table of contents;5
2;Preface;11
3;Acknowledgments;13
4;INTRODUCTION;14
4.1;1.1 Catalysis;14
4.2;1.2 Homogeneous catalysis;19
4.3;1.3 Historical notes on homogeneous catalysis;20
4.4;1.4 Characterisation of the catalyst;21
4.5;1.6 Ligands according to donor atoms;33
5;ELEMENTARY STEPS;42
5.1;2.1 Creation of a “vacant” site and co-ordination of the substrate;42
5.2;2.2 Insertion versus migration;43
5.3;2.3 ß-Elimination and de-insertion;48
5.4;2.4 Oxidative addition;49
5.5;2.5 Reductive elimination;52
5.6;2.6 a-Elimination reactions;54
5.7;2.7 Cycloaddition reactions involving a metal;55
5.8;2.8 Activation of a substrate toward nucleophilic attack;57
5.9;2.9 s-Bond metathesis;61
5.10;2.10 Dihydrogen activation;61
5.11;2.11 Activation by Lewis acids;63
5.12;2.12 Carbon-to-phosphorus bond breaking;65
5.13;2.13 Carbon-to-sulfur bond breaking;68
5.14;2.14 Radical reactions;70
6;KINETICS;75
6.1;3.1 Introduction;75
6.2;3.2 Two-step reaction scheme;75
6.3;3.3 Simplifications of the rate equation and the ratedetermining step;76
6.4;3.4 Determining the selectivity;80
6.5;3.5 Collection of rate data;83
6.6;3.6 Irregularities in catalysis;84
7;HYDROGENATION;86
7.1;4.1 Wilkinson's catalyst;86
7.2;4.2 Asymmetric hydrogenation;88
7.3;4.3 Overview of chiral bidentate ligands;97
7.4;4.4 Monodentate ligands;101
7.5;4.5 Non-linear effects;104
7.6;4.6 Hydrogen transfer;105
8;ISOMERISATION;112
8.1;5.1 Hydrogen shifts;112
8.2;5.2 Asymmetric Isomerisation;114
8.3;5.3 Oxygen shifts;116
9;CARBONYLATION OF METHANOL AND METHYL ACETATE;119
9.1;6.1 Acetic acid;119
9.2;6.2 Process scheme Monsanto process;124
9.3;6.3 Acetic anhydride;126
9.4;6.4 Other systems;128
10;COBALT CATALYSED HYDROFORMYLATION;135
10.1;7.1 Introduction;135
10.2;7.2 Thermodynamics;136
10.3;7.3 Cobalt catalysed processes;136
10.4;7.4 Cobalt catalysed processes for higher alkenes;138
10.5;7.5 Kuhlmann cobalt hydroformylation process;140
10.6;7.6 Phosphine modified cobalt catalysts: the Shell process;141
10.7;7.7 Cobalt carbonyl phosphine complexes;142
11;RHODIUM CATALYSED HYDROFORMYLATION;149
11.1;8.1 Introduction;149
11.2;8.2 Triphenylphosphine as the ligand;151
11.3;8.3 Diphosphines as ligands;163
11.4;8.4 Phosphites as ligands;171
11.5;8.5 Diphosphites;173
11.6;8.6 Asymmetric Hydroformylation;176
12;ALKENE OLIGOMERISATION;185
12.1;9.1 Introduction;185
12.2;9.2 Shell-Higher-Olefins-Process;186
12.3;9.3 Ethene trimerisation;194
12.4;9.4 Other alkene oligomerisation reactions;197
13;ALKENE POLYMERISATION;201
13.1;10.1 Introduction to polymer chemistry;201
13.2;10.2 Mechanistic investigations;209
13.3;10.3 Analysis by 13C NMR spectroscopy;212
13.4;10.4 The development of metallocene catalysts;216
13.5;10.5 Agostic interactions;222
13.6;10.6 The effect of dihydrogen;224
13.7;10.7 Further work using propene and other alkenes;225
13.8;10.8 Non-metallocene ETM catalysts;230
13.9;10.9 Late transition metal catalysts;232
14;HYDROCYANATION OF ALKENES;239
14.1;11.1 The adiponitrile process;239
14.2;11.2 Ligand effects;243
15;PALLADIUM CATALYSED CARBONYLATIONS OF ALKENES;248
15.1;12.1 Introduction;248
15.2;12.2 Polyketone;248
15.3;12.3 Ligand effects on chain length;265
15.4;12.4 Ethene/propene/CO terpolymers;271
15.5;12.5 Stereoselective styrene/CO copolymers;272
16;PALLADIUM CATALYSED CROSS-COUPLING REACTIONS;280
16.1;13.1 Introduction;280
16.2;13.2 Allylic alkylation;282
16.3;13.3 Heck reaction;290
16.4;13.4 Cross-coupling reaction;295
16.5;13.5 Heteroatom-carbon bond formation;299
16.6;13.6 Suzuki reaction;303
17;EPOXIDATION;308
17.1;14.1 Ethene and Propene oxide;308
17.2;14.2 Asymmetric epoxidation;310
17.3;14.3 Asymmetric hydroxylation of alkenes with osmium tetroxide;317
17.4;14.4 Jacobsen asymmetric ring-opening of epoxides;323
17.5;14.5 Epoxidations with dioxygen;325
18;OXIDATION WITH DIOXYGEN;328
18.1;15.1 Introduction;328
18.2;15.2 The Wacker reaction;329
18.3;15.3 Wacker type reactions;333
18.4;15.4 Terephthalic acid;336
18.5;15.5 PPO;341
19;ALKENE METATHESIS;346
19.1;16.1 Introduction;346
19.2;16.2 The mechanism;348
19.3;16.3 Reaction Overview;352
19.4;16.4 Well-characterised tungsten and molybdenum catalysts;353
19.5;16.5 Ruthenium catalysts;355
19.6;16.6 Stereochemistry;358
19.7;16.7 Catalyst decomposition;359
19.8;16.8 Alkynes;361
19.9;16.9 Industrial applications;363
20;ENANTIOSELECTIVE CYCLOPROPANATION;367
20.1;17.1 Introduction;367
20.2;17.2 Copper catalysts;368
20.3;17.3 Rhodium catalysts;372
21;HYDROSILYLATION;378
21.1;18.1 Introduction;378
21.2;18.2 Platinum catalysts;380
21.3;18.3 Asymmetric palladium catalysts;385
21.4;18.4 Rhodium catalysts for asymmetric ketone reduction;387
22;C–H FUNCTIONALISATION;393
22.1;19.1 Introduction;393
22.2;19.2 Electron-rich metals;395
22.3;19.3 Hydrogen transfer reactions of alkanes;400
22.4;19.4 Borylation of alkanes;401
22.5;19.5 The Murai reaction;402
22.6;19.6 Catalytic s-bond metathesis;403
22.7;19.7 Electrophilic catalysts;403
23;Subject index;408

Leseproben

Chapter 13
PALLADIUM CATALYSED CROSS-COUPLING REACTIONS (p. 271-272)

The new workhorse for organic synthesis

13. PALLADIUM CATALYSED CROSS-COUPLING REACTIONS

13.1 Introduction

The making of carbon-to-carbon bonds from carbocations and carbanions is a straightforward and simple reaction. Easily accessible carbanions are Grignard reagents RMgBr and lithium reagents RLi. They can be conveniently obtained from the halides RBr or RCl and the metals Mg and Li. They are both highly reactive materials, for instance with respect to water. The thermodynamic driving force for the formation of such reactive materials and their subsequent reactions is the formation of metal halides. The reactions of these carbon centred anions with polar compounds such as esters, ketones, and metal chlorides are indeed very specific and give high yields. The reaction of Grignard reagents with alkyl or aryl halides, however, is extremely slow giving many side-products, if anything happens at all. Note that this is also the key to the success of preparing Grignard type reagents(!), otherwise the partially formed RMgBr would react with the starting material RBr still present to give the "homocoupled" R-R. Exceptions are allylic and benzylic halides which react very fast amongst themselves during their synthesis. The Grignard reagents of this structure require specific practical procedures otherwise the homocoupled species are formed.

Reactions that can be expected for the reaction of an alkyl halide and a metal alkyl are depicted in Figure 13.1. The reaction may require several days at room temperature or may proceed in a few minutes, depending on the nature of the species. Many by-products may be formed. First a metal-halide exchange may occur. The resulting exchange products can give coupling products as well. Secondly, elimination reactions instead of C-C coupling can occur. Also, a radical reaction may take place. In summary, the yield and selectivity of this simple reaction will be surprisingly low. Only if a Grignard reagent is used in a coupling reaction with compounds that contain electrophilic carbon atoms, such as esters, ketones, and hetero-atom halides, the direct use of Grignard reagents (and related reagents) leads to high coupling efficiencies.

Figure 13.1. Products formed in a coupling reaction of a Grignard reagent and an alkyl halide

Thus, this reaction was of limited practical value until the transition metal catalysed cross-coupling reaction became known. Ever since, the "cross- coupling" reaction has found wide application in organic synthesis both in the laboratory and in industry. One might state that in any multi-step sequence for making an organic chemical, one of the steps involves a transition metal catalysed coupling reaction! The transition metal catalysts are usually based on palladium and sometimes nickel. In addition to organomagnesium and organolithium a great variety of organometallic precursors can be used. Also, many precursors can serve as starting materials for the carbocation. Last but not least, the ligand on the transition metal plays an important role in determining the rate and selectivity of the reaction. Here we will present only the main scheme and take palladium as the catalyst example, although many more metals have been found to be very useful. The reactions to be discussed are: allylic alkylation, Heck reaction, cross-coupling, and Suzuki reaction, a variant of the latter. Initially the cross-coupling chemistry focussed on carbon-tocarbon bond formation but in the last decade it has become also extremely useful for making carbon-to-heteroatom bonds. The organyl halide (or other anion used) involves in general an aryl, vinyl, or allylic species.