Cobalt Catalysis in Organic Synthesis

Methods and Reactions

Marko Hapke, Gerhard Hilt, Marko Hapke, Gerhard Hilt

• Publisher: Wiley-VCH
• Year: 2019
• Print ISBN: 9783527344505
• eBook ISBN: 9783527814862
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Provides a much-needed account of the formidable "cobalt rush" in organic synthesis and catalysis

Over the past few decades, cobalt has turned into one of the most promising metals for use in catalytic reactions, with important applications in the efficient and selective synthesis of natural products, pharmaceuticals, and new materials.

Cobalt Catalysis in Organic Synthesis: Methods and Reactions provides a unique overview of cobalt-catalysed and -mediated reactions applied in modern organic synthesis. It covers a broad range of homogeneous reactions, like cobalt-catalysed hydrogenation, hydrofunctionalization, cycloaddition reactions, C-H functionalization, as well as radical and biomimetic reactions.

• First comprehensive book on this rapidly evolving research area
• Covers a broad range of homogeneous reactions, such as C-H activation, cross-coupling, synthesis of heterocyclic compounds (Pauson-Khand), and more
• Chapters on low-valent cobalt complexes as catalysts in coupling reactions, and enantioselective cobalt-catalyzed transformations are also included
• Can be used as a supplementary reader in courses of advanced organic synthesis and organometallic chemistry

Cobalt Catalysis in Organic Synthesis is an ideal book for graduates and researchers in academia and industry working in the field of synthetic organic chemistry, catalysis, organometallic chemistry, and natural product synthesis.

1
Introduction to Cobalt Chemistry and Catalysis

Marko Hapke^1,2, and Gerhard Hilt³

¹Johannes Kepler University Linz, Institute for Catalysis (INCA), Altenberger Strasse 69,, 4040 Linz, Austria

²Leibniz Institute for Catalysis e.V. at the University of Rostock (LIKAT), Albert‐Einstein‐Strasse 29a,, 18059 Rostock, Germany

³Carl von Ossietzky Universität Oldenburg, Institut für Chemie, Carl‐von‐Ossietzky‐Strasse 9–11,, 26111 Oldenburg, Germany

1.1 Introduction

Cobalt (Co) is the first and lightest element among the group 9 transition metals, further members being rhodium (Rh), iridium (Ir), and meitnerium (Mt). In contrast to their significance in organic synthesis and catalysis, cobalt is by far the most abundant element of the group in the geosphere, compared with rhodium and iridium as its heavier congeners (Co:Rh:Ir = c. 10⁴ : 5 : 1) [1]. While rhodium and iridium complexes have been at the forefront of organotransition metal chemistry with relation to organic syntheses, steadily enabling novel and often unprecedented transformations of simple starting materials to complex products or opening the gate to novel fields of catalysis as has happened with C–H functionalisation reactions, cobalt stood back for a long time. Expression for the different significance of the three transition metals is also found in the literature, as monographs for either rhodium and iridium as catalyst metals for organic synthesis have already been published [2,3]. However, some direct comparisons of the application of group 9 metals for organic synthesis and catalysis can be found in the literature [4]. Next to its membership in the first row of the transition metals, relative abundance, and biorelevance, it is also considered a sustainable metal, among other elements in this nowadays particularly important field [5].

Cobalt (the name is derived from the German word “Kobold” meaning goblin, due to the behaviour and confusion with silver–copper ores in medieval mining) has been isolated for the first time in 1735 by the Swedish chemist Georg Brand, who also recognised its elemental character. It is an essential trace element for humans and animals, and its main purpose is the constitution of vitamin B₁₂ (cobalamin), which has an important role for the regeneration of erythrocytes. Cobalamines are organometallic compounds with cobalt–carbon bonds, possessing cobalt in the oxidation states +1 to +3, and provide the only known cobalt‐containing natural products.

Beside the importance for the human physiology, cobalt has evolved from an unwanted and downright abhorred element during silver and copper mining to a metal of strategic industrial importance and in recent years also a rising young star in homogeneous catalysis. How does this chemical version of “rags to riches” come into play? One modern reason is the importance of cobalt as metal used in high‐performance alloys (e.g. stellite), permanent magnets, rechargeable batteries, cell phones, and many more technical applications [6]. Requirements of our modern society with respect to the production of chemicals and materials also heavily rely on the late, rare, and rather expensive platinum group metals (PGM). The implementation of sustainability and efficiency thus leading the way to explore the earth‐abundant metals for both homogeneous and heterogeneous catalytic purposes [7,8].

From a chemical and catalytical point of view, cobalt already inherits the role of a major player in the awakening of homogeneous organometallic catalysis in the first half of the twentieth century [9]. Otto Roelen at Ruhrchemie (now Oxea) in Oberhausen discovered the “oxo synthesis” in 1938, today named hydroformylation reaction, and introduced HCo(CO)₄ as catalyst for this reaction. Still today beside rhodium as metal with higher reactivity cobalt complexes are used as catalysts. Basis for this reaction was work from Walter Hieber on the synthesis of carbonyl metallates via the so‐called “Hieber base reaction”, affording H₂Fe(CO)₄ by the reaction of Fe(CO)₅ with NaOH. Because for cobalt no mononuclear binary carbonyl compound is known, therefore the rel...

Table of contents

• Cover
• Table of Contents
• Preface
• Preface
• 1 Introduction to Cobalt Chemistry and Catalysis
• 2 Homogeneous Cobalt‐Catalysed Hydrogenation Reactions
• 3 Synthesis of CC Bonds by Cobalt‐Catalysed Hydrofunctionalisations
• 4 Cobalt‐Catalysed C–H Functionalisation
• 5 Low‐valent Cobalt Complexes in C–X Coupling and Related Reactions
• 6 Ionic and Radical Reactions of π‐Bonded Cobalt Complexes
• 7 Cobalt‐Catalysed Cycloaddition Reactions
• 8 Recent Advances in the Pauson–Khand Reaction
• 9 Cobalt‐Catalysed [2+2+2] Cycloadditions
• 10 Enantioselective Cobalt‐Catalysed Transformations
• 11 Cobalt Radical Chemistry in Synthesis and Biomimetic Reactions (Including Vitamin B12)
• Index
• End User License Agreement