Teichert J.F. (ed.) Homogeneous Hydrogenation with Non-Precious Catalysts

New York: Wiley-VCH, 2019. — 303 p.Catalytic homogeneous hydrogenations are among the most valuable catalytic transformations in synthetic chemistry due to the wide variety of substrates that can be converted with high atom economy, often in a stereoselective fashion. After Calvin reported the first homogeneous hydrogenations based on copper catalysts in 1938, however, the field of homogeneous hydrogenation was taken over by the much more efficient noble metal catalysts based on rhodium, iridium, and ruthenium. Tese catalysts dominate the field to this day, with many catalytic homogeneous hydrogenations being run on industrial scale. However, in the last two decades, a resurrection of interest in the first row transition metals as catalysts for homogeneous hydrogenations has taken place. In this sense, there is quite a parallel with the ligand development in asymmetric catalysis, in which the first chiral ligands had been monodentate, followed by a long-term rush on bidentate ligands, only to lead to chiral monodentate ligands to be rediscovered much later. Te 3d metals tend to be more readily available, which might be an important factor for large-scale processes. Te chapter on iron catalysts gives a good comparison on 3d metals vs. noble metals. Many of the processes studied so far are still quite limited in terms of catalyst efficiency, which hampers their applicability for industrial applications. But maybe even more importantly, though, catalysts based on 3d metals and other less frequently studied elements can offer new reactivity through reaction pathways less studied so far. Tis might be the most important aspect of these catalysts. In any case, an overview of the present methods so far with non-noble catalysts seems timely, and this book tries to offer a collection of the various catalysts that have been studied, mostly in an academic setting. Nevertheless, from an industrial vantage point, other factors might be of importance. Terefore, the stage is set by a specialist view on the challenges of homogeneous hydrogenation in an industrial and process setting. Tis lays out the main challenges for the following chapters (and the catalysts included in them) to be tackled. Certainly no easy tasks! Next to the transition metal catalysts and main group elements covered in this book, also other approaches to homogeneous hydrogenations in the broader sense are presented. New ways of activating dihydrogen by frustrated Lewis pairs (FLPs) have recently been undergoing a gold rush. A chapter devoted to this research area is included here to counterbalance well the transition metals with main group catalysts. Even though transfer hydrogenations are, strictly speaking, not “real” hydrogenations, two approaches have been included in this book to give the reader a good overview of other entries to reductive transformations. Consequently, the book ends with a perspective on transfer hydrogenations based
on enzymes and organocatalysts.