Implementation of Asymmetric Hydroformylation with Rhodium Bisdiazaphos Catalysts PDF Download
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Author: Bradley R. Jones
Publisher:
ISBN:
Category :
Languages : en
Pages : 394
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Book Description
The synthesis of complex organic molecules requires efficient routes for carbon-carbon bond formation. Selective, atom economic processes are highly desired for these transformations. One such reaction, hydroformylation, the formation of aldehydes by addition of CO and H2 across an alkene, fits these characteristics. Linear selective hydroformylation to generate alkyl aldehydes is one of the largest homogeneously catalyzed reactions performed industrially. However, asymmetric hydroformylation (AHF), generating chiral branched aldehydes is comparatively underdeveloped. Bisdiazaphospholane (BDP) ligands developed by the Landis group are highly regio- and enantioselective for AHF when paired with a rhodium metal center, but the limited availability and inconvenient synthesis have limited their use. An improved, scalable route to enantiopure BDP ligands featuring resolution of diastereomeric salts is described. This new route delivers BDP ligands with higher yield and purity while avoiding the use of chromatography. The potential industrial use of these ligands and AHF for the synthesis of fine chemicals is demonstrated through the development of AHF in flow, in collaboration with Eli Lilly. Additionally, synthetic applications of the aldehydes produced via AHF are expanded through new hydroacylation methodology. This approach utilizes the same functional groups which promote selective hydroformylation as directing groups for hydroacylation.
Author: Bradley R. Jones
Publisher:
ISBN:
Category :
Languages : en
Pages : 394
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Book Description
The synthesis of complex organic molecules requires efficient routes for carbon-carbon bond formation. Selective, atom economic processes are highly desired for these transformations. One such reaction, hydroformylation, the formation of aldehydes by addition of CO and H2 across an alkene, fits these characteristics. Linear selective hydroformylation to generate alkyl aldehydes is one of the largest homogeneously catalyzed reactions performed industrially. However, asymmetric hydroformylation (AHF), generating chiral branched aldehydes is comparatively underdeveloped. Bisdiazaphospholane (BDP) ligands developed by the Landis group are highly regio- and enantioselective for AHF when paired with a rhodium metal center, but the limited availability and inconvenient synthesis have limited their use. An improved, scalable route to enantiopure BDP ligands featuring resolution of diastereomeric salts is described. This new route delivers BDP ligands with higher yield and purity while avoiding the use of chromatography. The potential industrial use of these ligands and AHF for the synthesis of fine chemicals is demonstrated through the development of AHF in flow, in collaboration with Eli Lilly. Additionally, synthetic applications of the aldehydes produced via AHF are expanded through new hydroacylation methodology. This approach utilizes the same functional groups which promote selective hydroformylation as directing groups for hydroacylation.
Author: Piet W.N.M. van Leeuwen
Publisher: Springer Science & Business Media
ISBN: 0306469472
Category : Science
Languages : en
Pages : 291
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Book Description
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:
Publisher:
ISBN:
Category :
Languages : en
Pages : 298
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Book Description
The conversion of olefins into aldehydes by hydroformylation with rhodium catalysts is one of the largest homogeneously catalyzed industrial reactions, producing millions of tons of linear aldehydes per year. However, the production of chiral, branched aldehydes via asymmetric hydroformylation (AHF) remains underutilized in synthesis. To improve the application of rhodium BisDiazaphos catalyzed AHF, high selectivity for previously uninvestigated disubstituted olefins including enol esters and enamides is demonstrated, which yield more complex [alpha]-functionalized aldehyde building blocks. Additionally, process-scale asymmetric hydroformylation to yield chiral, enantioenriched aldehyde feedstocks has not yet been demonstrated. In collaboration with Eli Lilly, asymmetric hydroformylation in a research scale flow reactor is realized through the development of a flow synthesis of naproxen. To support scale-up of asymmetric hydroformylation technologies the synthesis of bisdiazaphospholane ligands is re-examined to optimize the cost of the material and synthesis on a larger scale is demonstrated. Access to enantiopure ligand via classical resolution in place of preparative SFC chromatography has also been developed, and will improve accessibility to selective AHF catalysts. Finally, the direct observation of catalytic intermediates and rate information in asymmetric hydroformylation by circulating high-pressure NMR will be described.
Author: Clarence E. Clark
Publisher:
ISBN:
Category :
Languages : en
Pages : 132
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Book Description
Author: Floriana Andreea Foarta
Publisher:
ISBN:
Category :
Languages : en
Pages : 458
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Book Description
Rhodium-catalyzed asymmetric hydroformylation is an atom efficient method to synthesize optically active aldehydes from simple alkenes, carbon monoxide and hydrogen. Such aldehydes serve as precursors to pharmaceuticals and fine chemicals. Efficient hydroformylation was demonstrated previously for many monosubstituted alkenes. Access to chiral aldehydes with more diverse branching substituents remains, however, limited. This work extends effective enantioselective hydroformylation to 1,2-disubstituted alkenes, particularly (Z)-enol esters and (Z)-enamides, and to 1,1'-disubstituted alkenes, predominantly alpha-substituted unsaturated esters. Functionalized aldehydes with tertiary and quaternary stereogenic centers are obtained with high stereo and regiocontrol at mild pressures in the presence of Rh-BisDiazaphos or Ph-BPE catalysts. The iterative application of the sequence Rh-BisDiazaphos catalyzed asymmetric hydroformylation of (Z)-enol esters / aldehyde oxidation / Ru catalyzed alkyne hydroacyloxylation enables catalytic, low-waste synthesis of sequence specific chiral oligoesters. This method demonstrates that short oligomers can be synthesized with sequence specificity and stereocontrol in the absence of coupling reagents and protecting groups.
Author: Xiao-Feng Wu
Publisher: John Wiley & Sons
ISBN: 3527831894
Category : Science
Languages : en
Pages : 1780
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Book Description
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:
Publisher:
ISBN:
Category :
Languages : en
Pages : 160
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Book Description
Rhodium-catalyzed hydroformylation, which converts alkenes to aldehydes via the addition of H2 and CO, is among the largest-volume industrial applications of homogeneous catalysis. However, fundamental questions concerning the origins of regio- and enantioselectivity in hydroformylation remain unanswered because key reaction intermediates have never been characterized. The rhodium-bis(diazaphospholane) complexes introduced by Landis and coworkers in 2005 are highly active and offer exceptional regio- and stereoselectivity. In this work, we report the interception and characterization of catalyst species using these complexes, including rhodium-alkyl complexes, which have never been characterized for any catalyst system, and rhodium-acyl complexes. By examining the kinetic and thermodynamic parameters of these species for the substrates styrene, vinyl acetate, allyl cyanide, and 1-octene, and comparing those results to catalytic selectivity, we demonstrate that the kinetic behavior of the acyl complexes can be considered a reasonable model for catalytic selectivity, offering an unprecedented window into this important but poorly-understood reaction.
Author: Ferenc Darvas
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110693674
Category : Technology & Engineering
Languages : en
Pages : 448
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Book Description
The fully up-dated edition of the two-volume work covers both the theoretical foundation as well as the practical aspects. Presenting the complete insight into driving a chemical reaction provides a deep understanding for new potential technologies. Updated overview on devices and new key concepts of experimental procedures. Vol. 2: Applications.
Author: Nicolas François Marie Pierson
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author:
Publisher:
ISBN:
Category : Alkenes
Languages : en
Pages : 190
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