Penny A. Chaloner

Bio: Penny A. Chaloner is an academic researcher from University of Sussex. The author has contributed to research in topics: Palladium & Rhodium. The author has an hindex of 24, co-authored 137 publications receiving 2154 citations.

Structural characterisation of a transient intermediate in rhodium-catalysed asymmetric homogeneous hydrogenation

Abstract: An unstable rhodium alkyl has been characterised by n.m.r. spectroscopy at low temperatures under the conditions of homogeneous hydrogenation.

Palladium-catalyzed cross-coupling reactions of organoboron compounds

Abstract: B. Other Catalyti; Process by Transition-Metal Complexes IV. Cross-Coupling Reaction A. Coupling of 1 -Alkenylboron Derivatives: Synthesis of Conjugated Dienes 6. Coupling of Arylboron Derivatives: Synthesis of Biaryls C. Coupling of Alkylboron Derivatives D. Coupling with Triflates E. Synthesis of Vinylic Sulfides F. Coupling with lodoalkanes: Alkyl-Alkyl CouDlino G. Coupling with Other Organic Halides and Boron Reagents V. Head-to-Tail Coupling VI. Carbonylative Coupling VII. Alkoxycarbonylation and Dimerization VIII. Conclusion 2457 2458 2458

The heck reaction as a sharpening stone of palladium catalysis.

Abstract: s, or keywords if they used Heck-type chemistry in their syntheses, because it became one of basic tools of organic preparations, a natural way to

New Chiral Phosphorus Ligands for Enantioselective Hydrogenation

Abstract: The increasing demand to produce enantiomerically pure pharmaceuticals, agrochemicals, flavors, and other fine chemicals has advanced the field of asymmetric catalytic technologies.1,2 Among all asymmetric catalytic methods, asymmetric hydrogenation utilizing molecular hydrogen to reduce prochiral olefins, ketones, and imines, have become one of the most efficient methods for constructing chiral compounds.3 The development of homogeneous asymmetric hydrogenation was initiated by Knowles4a and Horner4b in the late 1960s, after the discovery of Wilkinson’s homogeneous hydrogenation catalyst [RhCl(PPh3)3]. By replacing triphenylphosphine of the Wilkinson’s catalystwithresolvedchiralmonophosphines,6Knowles and Horner reported the earliest examples of enantioselective hydrogenation, albeit with poor enantioselectivity. Further exploration by Knowles with an improved monophosphine CAMP provided 88% ee in hydrogenation of dehydroamino acids.7 Later, two breakthroughs were made in asymmetric hydrogenation by Kagan and Knowles, respectively. Kagan reported the first bisphosphine ligand, DIOP, for Rhcatalyzed asymmetric hydrogenation.8 The successful application of DIOP resulted in several significant directions for ligand design in asymmetric hydrogenation. Chelating bisphosphorus ligands could lead to superior enantioselectivity compared to monodentate phosphines. Additionally, P-chiral phosphorus ligands were not necessary for achieving high enantioselectivity, and ligands with backbone chirality could also provide excellent ee’s in asymmetric hydrogenation. Furthermore, C2 symmetry was an important structural feature for developing new efficient chiral ligands. Kagan’s seminal work immediately led to the rapid development of chiral bisphosphorus ligands. Knowles made his significant discovery of a C2-symmetric chelating bisphosphine ligand, DIPAMP.9 Due to its high catalytic efficiency in Rh-catalyzed asymmetric hydrogenation of dehydroamino acids, DIPAMP was quickly employed in the industrial production of L-DOPA.10 The success of practical synthesis of L-DOPA via asymmetric hydrogenation constituted a milestone work and for this work Knowles was awarded the Nobel Prize in 2001.3k This work has enlightened chemists to realize * Corresponding author. 3029 Chem. Rev. 2003, 103, 3029−3069