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| Author | : Gabriela Ionescu |
| Publisher | : |
| Total Pages | : 112 |
| Release | : 2004 |
| Genre | : |
| ISBN | : 9789038629353 |
| Author | : Xiaowei Zhang |
| Publisher | : |
| Total Pages | : 208 |
| Release | : 2011 |
| Genre | : |
| ISBN | : |
| Author | : Piet W.N.M. van Leeuwen |
| Publisher | : Springer |
| Total Pages | : 286 |
| Release | : 2000-09-30 |
| Genre | : Science |
| ISBN | : 9780792365518 |
In the last decade there have been numerous advances in the area of rhodium-catalyzed hydroformylation, such as highly selective catalysts of industrial importance, new insights into mechanisms of the reaction, very selective asymmetric catalysts, in situ characterization and application to organic synthesis. The views on hydroformylation which still prevail in the current textbooks have become obsolete in several respects. Therefore, it was felt timely to collect these advances in a book. The book contains a series of chapters discussing several rhodium systems arranged according to ligand type, including asymmetric ligands, a chapter on applications in organic chemistry, a chapter on modern processes and separations, and a chapter on catalyst preparation and laboratory techniques. This book concentrates on highlights, rather than a concise review mentioning all articles in just one line. The book aims at an audience of advanced students, experts in the field, and scientists from related fields. The didactic approach also makes it useful as a guide for an advanced course.
| Author | : Renchang Tan |
| Publisher | : |
| Total Pages | : 111 |
| Release | : 2017 |
| Genre | : Hydroformylation |
| ISBN | : |
| Author | : Xin Zheng |
| Publisher | : |
| Total Pages | : 123 |
| Release | : 2015 |
| Genre | : Hydroformylation |
| ISBN | : |
Rhodium-catalyzed hydroformylation reaction is one of the most powerful homogeneous catalytic processes in the synthesis of aldehydes that can be widely applied in pharmaceuticals and fine chemicals. The design and synthesis phosphorus ligands combine with rhodium precursor used as catalysts is essentially important in the development of this reaction. This dissertation mainly focuses on the design, synthesis and application of efficient phosphorus ligands in rhodium-catalyzed hydroformylation. Asymmetric hydroformylation reaction (AHF), especially rhodium-catalyzed AHF has played a central role to construct chiral aldehydes in only one step. Although tons of chiral phosphorus ligands have been reported, few of them exhibited practicable enantioselectivities and regioselectivities. We report a new family of highly tunable bisphospholane ligands in the application of series of terminal and internal olefins, affording up to 88% for styrene derivatives, 93% ee for vinyl acetate derivatives, 93% ee for dihydrofuran and 96% for dihyropyrrole. A systematic screening different substituents on the ligand showed that ortho chloride on phenyl moiety was the successful structure, achieving the highest regio- and enantioselectivity. To expand the scope of substrates, especially the more challenging 1,1-disubstituted olefins, we first report the asymmetric hydroformylation of 1,1-disubstituted allylphthalimides by employing chiral ligand 1,2-bis[(2S, 5S)-2,5-diphenylphospholano]ethane [(S, S)-Ph-BPE] to yield a series of beta-3-aminoaldehydes with up to 95% enantioselectivity. This asymmetric procedure provides an efficient alternative route to prepare chiral beta-3-amino acids and alcohols that are key structural elements of beta-aminobutyric acid. Hydroaminomethylation is the tandem reaction of hydroformylation/hydrogenation. This efficient reaction is utilized to build nitrogen-containing compounds, which are interesting in pharmaceutics and fine chemicals. In this chapter, we disclose the synthesis of 4-aryl-2,3-dihyropyrrole derivatives by rhodium-catalyzed intramolecular hydrominometylation reaction with up to 99% yield.
| Author | : Bonan Cao |
| Publisher | : |
| Total Pages | : 130 |
| Release | : 2013 |
| Genre | : Chirality |
| ISBN | : |
Transition-metal-catalyzed reactions have become powerful tools in the production of pharmaceuticals and fine chemicals. In the past decades, asymmetric catalysis, especially chiral rhodium catalysts, hold an increasing role of efficiently building up chirality. In this dissertation, we will focus on the development of several rhodium phosphorus catalysts and their applications in hydroformylation and asymmetric hydrogenation reactions. Chapter I outlined the development of a new family of sterrically rigid hybrid phosphine-phosphoramidite ligands. The new catalyst system shows excellent compatibility versus styrene, vinyl acetate, allyl cyanide and their derivatives. The relationship between the enantioselectivity and the substituent on ligands is investigated by systematic variation on the ligand structures. In chapter II, further application of phosphine-phosphoramidite ligands in asymmetric hydroformylation of N-allylamides and N-allylsulfonamides provides a new approach to chiral [beta]2-amino aldehydes, acids, and alcohols for pharmaceutical and synthetic chemistry. Up to 99% ee and 9700 turnovers stands as the best result achieved in this type of hydroformylation reaction. Chapter III focuses on the synthesis of a series of aryl substituted dihydropyrroles via this hydroformylation. The significant improvement in reactivity and chemoselectivity suggests a potential application in building large heterocycles in an atom efficient fashion. In chapter IV, I report a successful monodentate phosphoramidite ligand for the catalytic asymmetric hydrogenation of dehydroamino esters. The easy modulared structure allowed us to further expand the scope of the ligand.
| Author | : Paul C. J. Kamer |
| Publisher | : John Wiley & Sons |
| Total Pages | : 673 |
| Release | : 2012-05-09 |
| Genre | : Technology & Engineering |
| ISBN | : 1118299701 |
Over the last 60 years the increasing knowledge of transition metal chemistry has resulted in an enormous advance of homogeneous catalysis as an essential tool in both academic and industrial fields. Remarkably, phosphorus(III) donor ligands have played an important role in several of the acknowledged catalytic reactions. The positive effects of phosphine ligands in transition metal homogeneous catalysis have contributed largely to the evolution of the field into an indispensable tool in organic synthesis and the industrial production of chemicals. This book aims to address the design and synthesis of a comprehensive compilation of P(III) ligands for homogeneous catalysis. It not only focuses on the well-known traditional ligands that have been explored by catalysis researchers, but also includes promising ligand types that have traditionally been ignored mainly because of their challenging synthesis. Topics covered include ligand effects in homogeneous catalysis and rational catalyst design, P-stereogenic ligands, calixarenes, supramolecular approaches, solid phase synthesis, biological approaches, and solubility and separation. Ligand families covered in this book include phosphine, diphosphine, phosphite, diphosphite, phosphoramidite, phosphonite, phosphinite, phosphole, phosphinine, phosphinidenene, phosphaalkenes, phosphaalkynes, P-chiral ligands, and cage ligands. Each ligand class is accompanied by detailed and reliable synthetic procedures. Often the rate limiting step in the application of ligands in catalysis is the synthesis of the ligands themselves, which can often be very challenging and time consuming. This book will provide helpful advice as to the accessibility of ligands as well as their synthesis, thereby allowing researchers to make a more informed choice. Phosphorus(III) Ligands in Homogeneous Catalysis: Design and Synthesis is an essential overview of this important class of catalysts for academic and industrial researchers working in catalyst development, organometallic and synthetic chemistry.
| Author | : Kexuan Huang |
| Publisher | : |
| Total Pages | : 103 |
| Release | : 2014 |
| Genre | : Ligands |
| ISBN | : |
| Author | : Xiao-Feng Wu |
| Publisher | : John Wiley & Sons |
| Total Pages | : 1780 |
| Release | : 2022-01-14 |
| Genre | : Science |
| ISBN | : 3527831894 |
The Chemical Transformations of C1 Compounds A comprehensive exploration of one-carbon molecule transformations The chemistry of one-carbon molecules has recently gained significant prominence as the world transitions away from a petroleum-based economy to a more sustainable one. In The Chemical Transformations of C1 Compounds, an accomplished team of chemists delivers an in-depth overview of recent developments in the field of single-carbon chemistry. The three-volume book covers all major C1 sources, including carbon monoxide, carbon dioxide, methane, methanol, formic acid, formaldehyde, carbenes, C1 halides, and organometallics. The editors have included resources discussing the main reactions and transformations into feedstock chemicals of each of the major C1 compounds reviewed in dedicated chapters. Readers will discover cutting-edge material on organic transformations with MeNO2, DMF, DCM, methyl organometallic reagents, CCl4, CHCl3, and CHBr3, as well as recent achievements in cyanation reactions via cross-coupling. The book also offers: Thorough introductions to chemical transformations of CH4, methods of CH4 activation, chemical transformations of CH3OH and synthesis alkenes from CH3OH Comprehensive explorations of the carbonylation of MeOH, CH2O in organic synthesis, organic transformations of HCO2H, and hydrogen generation from HCO2H Practical discussions of the carbonylation of unsaturated bonds with heterogeneous and homogeneous catalysts, as well as the carbonylation of C(sp2)-X bonds and C(sp3)-X bonds In-depth examinations of carbonylative C-H bond activation and radical carbonylation Perfect for organic and catalytic chemists, The Chemical Transformations of C1 Compounds is also an ideal resource for industrial chemists, chemical engineers, and practitioners at energy supply companies.
| Author | : Julia Wildt |
| Publisher | : |
| Total Pages | : 360 |
| Release | : 2017 |
| Genre | : |
| ISBN | : |
Hydroformylation is one of the largest homogenously catalyzed transformations in industry, leading to important aldehyde product from alkene starting materials. Asymmetric hydroformylation on the other hand is underdeveloped. The challenge is to maintain high regio- and enantioselectivities for the resulting branched aldehyde. Extensive research is performed on the development and synthesis on chelating bisphosphorus ligands to help control the desired selectivities. However, the substrate scope is only limited for any single ligand. With the discovery of the class of bisdiazaphospholane ligands by Landis and coworker, new paths were opened in addressing a broad scope of substrates over the years. The ligand (S,S,S)-BisDiazaPhos represents a state-of-the-art ligand, that can hydroformylate a variety of substrate with fast rates, while maintaining both high regio- and enantioselectivity. This work focuses on the synthesis of novel 3,4-diazaphospholane ligands to expand the existing library and to address new substrate or improve upon existing selectivities. Chapter 3 shows that racemic 2,5-phenyl-and naphthyl-substituted bisdiazaphospholanes, containing the acylhydrazine backbone can be reduced with BH3 to yield alkylhydrazine based bisdiazaphospholanes. These reduced ligands have been tested in the rhodium-catalyzed hydroformylation of different substrate classes. Interestingly, the regioselectivity with the reduced ligands was improved compared to their non-reduced analogues. This improvement is considered to come from the conformational change in the ring structure, where an increased torsion angle within the ring correlates to higher regioselectivities. A steric quadrant model is used to rationalize the improved regioselectivities for the reduced bisdiazaphospholanes. Chapter 4 describes the development of boronate bearing diazaphospholanes as directing or scaffolding ligands for the purpose of intramolecular hydroformylation of the challenging substrate class of allylic and homoallylic alcohols. This concept takes advantage of functional groups that can coordinate covalently to a substrate and datively to a metal center, leading to improved selectivity and reactivity compared to a non-directed transformations. The synthesis of these novel boronate bearing diazaphospholanes is laid out. The directed hydroformylation of allylic substrates was not observed with mono-diazaphospholanes. The synthesis towards chelating bisdiazaphospholane is described and thought to have the potential to gain further insights into the directing effects of bisdiazaphospholane structures.
