Special Issue: Recent Advances in Transition‐Metal Catalysis

Abstract

This special issue “Recent Advances in Transition-Metal Catalysis” containing forty-two personal accounts and seven record reviews, discusses the ascendancy of transition metals in modern organic synthesis. The included articles portray the manifold application of transition metals in various processes such as addition/cyclization reactions, asymmetric synthesis, olefin metathesis reactions, coupling reactions, C−H bond activation/functionalization reactions. Additionally, reports describing novel organic transformations based on the employment of transition-metal catalysis in the fields of radical chemistry and materials science are also presented in this collection. Catalysis, considered as the heart of modern science, has changed the paradigm of constructing molecular complexity with great selectivity and efficiency. Over the years, the field of catalysis has made a paramount impact on science and technology because of its rapid emergence in the development of new synthetic methodologies that are not only greener but also cost, time, yield, and labor-effective. The legacy of catalysis in synthetic organic chemistry has mainly been promoted by two key players: transition-metal catalysis and organocatalysis. The scientific contribution and societal impact of these two types of catalysis has been acknowledged with the Nobel Prizes in the year 2001 (Knowles, Noyori, and Sharpless for stereoselective catalysis), 2005 (Chauvin, Grubbs, and Schrock for olefin metathesis), 2010 (Heck, Negishi, and Suzuki for palladium-catalyzed cross-coupling reactions) and recently in 2021 (List and MacMillan for asymmetric organocatalysis). Although it is almost impossible to compare which type of catalysis (metal- or organo-catalysis) is superior because of their unique characteristic reactivity profiles, transition-metal catalysis has traditionally been considered as a strong pillar of catalysis and has mostly dominated the field of organic synthesis. The ability of transition metals to shuttle between different oxidation states while forming complexes with the reagents in a catalytic cycle allows them to achieve unprecedented and non-conventional transformations. Moreover, the reactivity and selectivity of these metal complexes can be fine-tuned according to the requirement of the catalytic process with the assistance of different factors, such as steric and electronic nature of metal-coordinated ligands and counterions. Thereby, these processes are in general highly efficient and hold tremendous potential for the development of new synthetic methodologies to access diverse array of molecular scaffolds from readily available feedstock with high chemo-, regio-, and stereoselectivity. This thematic issue, entitled “Recent Advances in Transition-Metal Catalysis”, focuses on the scientific developments and contributions from nearly 50 groups across the globe in accomplishing various transition-metal-catalyzed transformations that occupy the frontiers of organic synthesis. Innovative research works from Jen-Chieh Hsieh on transition-metal-catalyzed addition/cyclization reactions of C−N multiple bonds and from the group of Atanu Modak/Debabrata Maiti on decarbonylation methodology using transition metals to synthesize arenes are described in this special issue. A review article from the group of Sanjay Batra details the transition-metal-catalyzed aminocarbonylation and amidation reactions of nitroarenes and thereby giving access to amide bonds in functional molecules. In this issue, Marko Hapke and S. S. V. Ramasastry have summarized their works on cobalt-catalyzed [2+2+2] cycloaddition reactions and on palladium-catalyzed transformations to construct novel molecular scaffolds utilizing Alder-ene type cycloisomerization and C−H functionalization. The group of Ramasamy Vijaya Anand has provided a detailed account of their venture into transition-metal-catalyzed synthesis of oxygen- and nitrogen-based heterocycles from para-quinone methides. Alongside these research articles, strategies dealing with the construction of carbon–heteroatom bonds are of utmost curiosity. In this regard, Chin-Fa Lee/Satpal Singh Badsara have provided an inclusive discussion on the generation of carbon–sulfur bonds. In addition, a detailed description on the carbon–fluorine bond formation reactions from the group of Gavin Chit Tsui, has also been described in this issue. Among several other transition-metal-catalyzed methodologies applied to streamline the formation of molecular scaffolds, an approach exploiting the carbophilic activation property of coinage metals (Cu, Ag, Au) into harnessing various cyclization reactions has been highlighted by Chepuri V. Ramana, Véronique Michelet, Hiroaki Ohno, Paul W. Davies, Akhila S. Sahoo, and Nitin T. Patil. Furthermore, transition metals have also acquired profound interest in the synthesis of various natural product scaffolds as exemplified from the reports of Alakesh Bisai, Ravi S. Lankalapalli/Kokkuvayil Vasu Radhakrishnan and Adrien Quintard. Transition-metal catalysis has emerged as the most effective and reliable approach towards achieving asymmetric chemical transformations. The ability of transition-metal complexes to impart asymmetry in organic molecules through chiral ligands and chiral counterions has provided an access point to the enantioselective synthesis of numerous compounds. Detailed coverages on transition-metal-catalyzed stereoselective desymmetrization of prochiral cyclohexadienones by Rambabu Chegondi and on enantioselective synthesis of chiral amines using a Rh(I)/bicyclo[2.2.1]heptadiene catalyst system by Hsyueh-Liang Wu are portrayed in this issue. A review from the group of Miquel Costas describing enantioselective aliphatic C−H oxidation reactions utilizing bioinspired chiral complexes has also highlighted the pivotal role played by transition metals in this field. With the ever-growing interest in carbon–carbon bond forming reactions, transition-metal-catalyzed olefin metathesis reactions have acquired significant attention from the scientific community. Over the years, a vivid development in metathesis chemistry has been achieved through the improved understanding to the effect of ligand modification in the metal coordination sphere. In this special issue, a joint venture based on a distinct class of ruthenium olefin metathesis catalysts featuring unsymmetrical N-heterocyclic carbene ligands and its industrial implementation has been reported by Karol Grela/Anna Kajetanowicz/Louis Monsigny. Notably, the importance of asymmetric olefin metathesis reactions in the preparation of planar-chiral transition-metal complexes has been reflected through a report by Masamichi Ogasawara. Coupling reactions, one of the most widely explored transformations catalyzed by transition metals, have received notable attention from organic chemists over the years. Muriel Durandetti and Kouki Matsubara in their independent articles have described their endeavors on nickel-catalyzed cross-coupling reactions. On the same note, the group of Masakazu Nambo/Cathleen M. Crudden has provided an in-depth account of the transition-metal-catalyzed cross-coupling reactions of benzylic sulfones enabling new desulfonylative transformations. Furthermore, research works from the group of Ming Bao on palladium-catalyzed three-component coupling reactions and from Beeraiah Baire/Siddique Khan on iron-catalyzed coupling reactions of alkynes and alcohols have demonstrated the synthetic application of transition metals. Owing to the omnipresence of inert C−H bonds in organic molecules, transition-metal-catalyzed C−H bond activation/functionalization reactions offer the rapid construction of molecular complexity in step- and atom-economical manner. Detailed discussions on iridium and nickel-catalyzed C−H activation reactions have been recorded by the groups of Takahiro Nishimura and Benudhar Punji, respectively. In this domain, a special emphasis has been given on the elegant approach of directing group-assisted regio-controlled C−H bond functionalization reactions through the independent works by Mahiuddin Baidya, Sungwoo Hong, and Tharmalingam Punniyamurthy. A comprehensive review article comprising of tandem C−H bond activation and subsequent carbene migratory insertion reactions has been delineated by Manmohan Kapur. In the same line, the group of Rajarshi Samanta has reviewed several transition-metal-catalyzed C−H insertion reactions on the in situ generated metal carbenes and nitrenes, for achieving various functionalized nitrogen-containing heterocycles. Two more interesting accounts consisting the in situ generation of metallocarbenes and their subsequent transformations have been outlined by the group of Pazhamalai Anbarasan/Dongari Yadagiri, and the group of Chandra M. R. Volla. Furthermore, various catalytic transformations involving the activation of strong C−F, C−S, and C−N bonds have also been thoroughly surveyed by Yasushi Nishihara, Hideki Yorimitsu, and Junfeng Zhao, respectively. In achieving novel synthetic organic transformations, radical chemistry has acquired considerable recognition; however, the reactivities of radicals are difficult to harness owing to their inherent instability. In this scenario, the integration of transition-metal catalysis with radical chemistry has opened new avenues to achieve controlled site-selective reactions by stabilizing the radicals and protecting them from being quenched through undesired homo-coupling or fragmentation. In this thematic issue, the group of Bhisma K. Patel has provided an overview on their contribution in transition-metal-catalyzed peroxide-based radical reactions. Another research endeavor on this intersection has been outlined by Chi-How Peng describing the employment of organo-cobalt complexes in reversible-deactivation radical polymerization. The arsenal of transition-metal catalysis has been further enriched with its enormous application in the field of materials science. Two of such representative accounts have been described in this issue. In one report, the group of Ching-Yuan Liu has summarized various step-saving viable synthetic pathways to access functional π-conjugated materials, such as thiophene-based small molecules for optoelectronic applications. In another report, Yohji Misaki has discussed the palladium-catalyzed periphery modification of tetrathiafulvalene and their use as functional materials. Apart from the above-mentioned articles, a few interesting research works canvassing different transition-metal-catalyzed reactions have also been presented in this issue. The group of Xuefeng Jiang has showcased a versatile approach of transition-metal-catalyzed introduction of hypervalent sulfur to access SO2-containing compounds. A personal account from the group of Yuichiro Mutoh/Shinichi Saito describing N-heterocyclic carbene ligated ruthenium-catalyzed (Z)-selective hydrosilylation and hydroboration of terminal alkynes, and another account from the group of Hiroto Yoshida demonstrating copper-catalyzed borylation and stannylation reaction have also been discussed in this issue. The utilization of transition-metal catalysis has further been emphasized through the reports by Yasuyuki Ura on palladium-catalyzed oxidative acetalization and Wacker-type oxidation of terminal alkenes with anti-Markovnikov selectivity, and by Ekambaram Balaraman on first-row transition-metal-catalyzed acceptorless dehydrogenation reactions. In another report, the research group of Yoshikazu Horino/Toshinobu Korenaga has portrayed their achievements in unfolding the versatile reactivity of metalloid-substituted π-allylpalladium complexes. Compilation of this thematic issue in the challenging years 2020/2021 was a difficult task and therefore, we want to take this opportunity to thank all the authors for their invaluable contribution. We are thrilled to receive such largesse from our colleagues (49 articles) who have spent their precious time to bring this timely opus to the scientific community. Furthermore, this special issue could not have been possible without the support of Dr. Dinesh Talwar (Wiley-VCH) who worked diligently to assemble the articles in a nice and holistic manner. We hope that the readers will enjoy reading this issue and will find it beneficial for their future research endeavors. About Hideki Yorimitsu: Hideki Yorimitsu was born in Kochi, Japan, in 1975. He obtained his Ph.D. in 2002 from Kyoto University under the tutelage of Professor Koichiro Oshima. He then served as a JSPS postdoctoral fellow with Professor Eiichi Nakamura at the University of Tokyo. Subsequently, he became Assistant Professor (2003) and Associate Professor (2008) in the Graduate School of Engineering, Kyoto University. In 2009, he moved to the Graduate School of Science, Kyoto University, where he was promoted to Full Professor in 2015. He was Project Leader of ACT-C (2012–2018) and is currently Project Leader of CREST, Innovative Reaction (2019–), supported by Japan Science and Technology Agency (JST). He was Visiting Scholar of Institute for Molecular Science (2014–2016) and is Honorary International Chair Professor of National Taipei University of Technology (2018–2020). About Martin Kotora: Martin Kotora was born in Pilsen, Czech Republic, in 1963. He obtained a MSc degree in 1986 from Charles University in Prague, a PhD degree in 1991 from the Institute of Chemical Process Fundamentals, the Czech Academy of Sciences, under guidance of Dr. Milan Hájek. In 1993 he joined Prof. Tamotsu Takahashi's group at the Institute for Molecular Science in Okazaki as a JSPS postdoctoral fellow. His second postdoctoral stay started in 1995 in Prof. Ei-ichi Negishi's group to Purdue University. In 1996 he joined the faculty at the Catalysis Research Center, Hokkaido University. After four years, in 2000, he returned to his alma mater (Charles University) to begin an independent career. In 2006 he was promoted Full Professor. His group's research interests center around transition-metal complex catalyzed or mediated reactions and their application in organic synthesis. About Nitin T. Patil: Nitin T. Patil was born in Jalgaon (Maharashtra), India, in 1975. He completed his doctoral studies from the University of Pune in 2002 under the supervision of Prof. Dilip D. Dhavale. Subsequently, he joined Prof. Christoph Schneider's group as a postdoctoral fellow at the University of Göttingen, Germany. In November 2002, he moved to Tohoku University, Japan, as a JSPS postdoctoral fellow to work with Prof. Yoshinori Yamamoto, where later on he was appointed as an Assistant Professor. In June 2006, he joined Prof. K. C. Nicolaou's laboratory at ICES, Singapore, and later at The Scripps Research Institute, USA. He began his independent career in September 2008 at CSIR-IICT, Hyderabad, and subsequently moved to CSIR-NCL, Pune, in August 2013. Since July 2017, he has been an Associate Professor at the Department of Chemistry, IISER Bhopal.

Topics & Concepts