It is a tremendous honor and a sheer delight to have been asked to write an introduction for this important and timely tome entitled “Asymmetric Hydrogenation and Transfer Hydrogenation,” edited by my dear friends Dr. Virginie Vidal and Dr. Phannarath (Poki) Phansavath, themselves notable contributors to the field. This book will certainly stand as a landmark contribution that not only summarizes the state of the current art for this useful reaction genre but also sets the stage for practitioners to explore vistas of future importance.

As many readers will recognize, (transfer) hydrogenation has a very long and distinguished history in organic chemistry, playing a key role in the field and indeed perhaps serving as a bellwether for the development of synthetic methods in the discipline as a whole. Paul Sabatier (Nobel Prize, 1912) has been credited with the first advances in alkene hydrogenation in the late 1890s, and it was Knoevenagel who reported the first transfer hydrogenation reaction in 1903 – essentially a dimerization process involving disproportionation between identical donor and acceptor units promoted by palladium black in a heterogeneous transformation. Two decades later (1925) came the famous Meerwein–Ponndorf–Verley reaction, a redox coupling between a different donor and acceptor. Several more decades passed (1960s) before homogeneous transition metal catalysts were developed for both hydrogenation (e.g. Wilkinson’s catalyst) and transfer hydrogenation, where Henbest, Mitchell, and coworkers hydrogenated carbonyls to alcohols using isopropanol as the hydride transfer reagent. This was subsequently followed by transition metal‐catalyzed asymmetric processes for carbonyl, imine, alkene, and related reductions, in which the seminal work of Henri Kagan culminated in the award of the Nobel Prize in Chemistry to Noyori and Knowles for their contribution to the field in 2001. Thus began the explosive flurry of activity, leading to the current status of the field – a cluster of reactions that occupies an exalted status within the discipline owing to the fact that they are being used in the fragrance, flavors, pharmaceutical, and agrochemical industries worldwide on ton scale. Flow techniques, biocatalysis, and organocatalytic methods round out more recent additions to the armamentarium available to practitioners of the art of organic synthesis, pointing to exciting opportunities for further exploration.

Homogeneous catalytic asymmetric (transfer) hydrogenation transformations thus quite rightfully deserve the attention they are receiving in this volume. As pointed out throughout, these reactions represent perhaps the most efficacious and facile means to access enantiomerically enriched molecules, principally because they serve as supreme examples of atom‐economical, environmentally sustainable reactions. Virginie and Poki have assembled a star‐studded group of individuals to share their deep wisdom and rich experience on this topic with members of the community. Each contributor is a highly qualified expert in their field, and the result is a magnificently crafted contribution that will be of value for years to come. Congratulations to the authors Virginie and Poki for this marvelous effort!

Gary Molander

Philadelphia, PA, USA

May 6, 2020