In the late 1960s and through the 1970s, organometallic chemistry emerged from being a subfield of inorganic chemistry, where the interest was in boding and structure, to a field in its own right with chemists trained in inorganic or organic chemistry. The organic chemists brought reactivity to the field and helped to move organometallic chemistry into catalysis. The pioneering work of Collman, Vaska, and Halpern among others defined the basic mechanisms of the field and provided the basis for the application of this new field in organic transformations and organic synthesis. Now, most pharmaceuticals and natural product syntheses involve one, if not more, catalytic steps. The study of asymmetric hydrogenation and the ligands and mechanisms that controlled these processes paved the way for the discovery of a wide array of asymmetric processes. The structural flexibility of homogeneous catalysts and the wide array of ligands now available have resulted in most catalytic processes now being capable of producing products in high asymmetric purity. Heterogeneous catalysts, although they are generally favored for ease of processing, do not provide the flexibility required for more precise transformations. The rise of homogeneous catalysts has required the development of processes and methods that allow homogeneous catalysts to be exploited in practical large‐scale processes.

Colacot (Millipore Sigma, a business of Merck KGaA) and Seechurn (Johnson Matthey), the editors of this book, have addressed these issues. After authoring the first chapter, which provides the historical background for the development of homogeneous catalysts and the basic mechanisms, they have chosen an outstanding group of authors to provide specific information about the practical aspects of the conversion of laboratory‐scale reactions into real processes. Most of the processes are demonstrated by real examples. Themes of the chapters emphasize new developments in the pharmaceutical industry processes such as flow and continuous processes and the development of catalysts based on earth‐abundant metals.

Chapters 2 and 3 discuss the advantages of continuous flow process. For example, the safe use of oxygen with organic solvents can be mitigated by the use of flow systems, and efficient processes can be developed for homogeneous reactions on scale. Particularly interesting is the use of the Buchwald–Hartwig reaction in a flow system with the efficient removal of the residual palladium catalysts. The second of the two chapters describes the methods for the use of low‐temperature processes in the production of materials on a large scale, which involve reactive and environmentally sensitive reagents. These two chapters provide a detailed update on flow processes with the goal of increasing the use of flow processes in homogeneous processes. These processes regain some of the advantages that were traditional with heterogeneous catalysts while maintaining the selectivity of homogeneous processes. In a related process development, Chapter 8 describes the use of another “nanoreactor”: micelles in water. In this chapter, the developments of traditional homogeneous cross‐coupling reactions such as Heck and Suzuki–Miyaura in aqueous environments using a micelle environment are described. Carrying out the reactions in nanoreactors – micelles – results in interesting new selectivity and reactivity. From a process chemist's perspective, micelle‐enabled processes can offer benefits such as the replacement of toxic organic solvents, reduced PMI value, improved reaction yields, high purity of API with reduced metal contents, and high cost efficiency.

As processes are scaled, the costs of the metal and ligands become more important. Chapters 4 and 5 describe the development of processes that are traditionally carried out using precious metals by rather employing either nickel or iron. These successful examples will encourage further development of efficient selective catalysts based on earth‐abundant metals. In spite of potential costs, palladium catalysts have been shown to have a wide array of activities and selectivities. Chapter 6 demonstrates an outstanding example of the use of palladium in the commercial synthesis of beclabuvir utilizing the selectivity of palladium catalysts. Although, earth‐abundant metals can take the place of palladium in a number of reactions, or rather complement Pd, the efficiency and selectivity of many palladium catalysts will ensure that it continues to be used in the pharmaceutical and fine chemical industry for many years to come.

Chapters 7, 9, and 10 cover specific reactions in process chemistry. The chapter on homogeneous hydrogenation provides a guide to the use of asymmetric hydrogenation in the synthesis of complex structures on a commercial scale. Asymmetric hydrogenation is one of the oldest and most used asymmetric processes in synthesis. This up‐to‐date guide provides the highlights of this field and helps to simplify the vast literature. In contrast, CH activation in complex synthesis is one of the newer areas of emphasis. For a number of years, there has been the recognition of the value of being able to functionalize CH bonds directly, although C–H activation has not risen up like the cross‐coupling reactions for industrial process. Therefore, the editors were conscientious enough to add a chapter on this topic. As is demonstrated in Chapter 7, this promise is now being realized as demonstrated by the use of a CH activation process in the synthesis of important compounds such as Merck's anacetrapib, sartans, etc. Olefin metathesis has been an important topic in academic synthesis for several decades; Phillips provides examples where this background of reactivity is now being translated into key structures for the pharmaceutical industry. He provides particularly good coverage of the important topics such as catalyst stability and removal that are required for the use of a homogeneous catalyst in a larger process.

The last chapter takes homogeneous catalysts outside of the applications in the pharmaceutical industry to the conversion of biomass‐derived materials into chemical feedstocks. As many biomass sources are solids, a soluble catalyst is particularly suited for such applications. Although they focus on the conversion of carboxylic acids into olefins, the techniques and strategies would apply to many other such processes and can be developed for potential applications in industry.

It is particularly pleasing to see the evolution of organometallic chemistry into catalysts for extremely useful organic transformations. The basic principle and reaction mechanisms that were developed in the early decades of the area are now the basis for major processes that open the efficient synthesis of an amazing array of new chemical structures that have revolutionized how present‐day bioactive materials are designed and prepared. Colacot and Seechurn have used their broad experience in new catalyst development, organic synthesis, and process chemistry involving homogeneous catalysts to assemble an outstanding team of authors from all over the world to highlight the important developments required to fulfill the promise of catalysis in organic synthesis for the twenty‐first century. This is a very timely book for both academia and industry chemists and engineers to understand how academic concepts are translated into industries with a wide variety of important molecules as depicted in the cover of the book.

Robert Howard Grubbs

Division of Chemistry and Chemical Engineering

California Institute of Technology, Pasadena, CA 91125 USA

(626) 395 6003, rhg@caltech.edu

Prof. Grubbs Biography

B.A. and M.S. Chemistry, University of Florida, Gainesville, Florida, 1963 and 1965. Ph.D., Chemistry, Columbia University, New York, 1968. NIH Postdoctoral Fellow, Chemistry, Stanford University, 1968‐69. He is the Victor and Elizabeth Atkins Professor of Chemistry at the California Institute of Technology, Pasadena, California, USA, and a faculty member since 1978. He was a faculty member at Michigan State University from 1969 to 1978.

The Grubbs group discovers new catalysts and studies their fundamental chemistry and applications. For example, a family of catalysts for the interconversion of olefins, the olefin metathesis reaction, has been discovered in the Grubbs laboratory. In addition to their broad usage in academic research, these catalysts are now used commercially. Other projects involve the design and synthesis of materials for use in medical applications. He has also been involved in the translation of technology through the founding of five companies.

His awards have included the Nobel Prize in Chemistry (2005) and 10 ACS National Awards. He was elected to the National Academy of Sciences (1989), Fellow of the American Academy of Arts and Sciences (1994), the Honorary Fellowship of the Royal Society of Chemistry (2006), Fellow of National Academy of Inventors, National Academy of Engineering (2015), and Foreign Member of the Chinese Academy of Sciences (2014) and of Great Britains's Royal Society (2017). He has 655+ publications and 160+ patents based on his research.