Rhodium Asymmetric Hydrogenation Observed during its Exponential Growth Phase

Abstract

The field of asymmetric hydrogenation grew rapidly after the early 1970s. What had begun as a demonstration of enantioselectivity in catalysis by purely chemical means became an important tool both for academic research and for industry. Right from the beginning, a question was posed as to how relatively simple catalysts were able to generate such unprecedented levels of stereoselectivity. This article provides an account of Oxford-based contributions to the field of rhodium complex catalyzed asymmetric hydrogenation from 1978 onward, when the initial realization of this practical catalytic method for synthesis of single enantiomers had already been achieved. NMR-based experiments that help to elucidate the structures of reactive intermediates in catalysis are strongly emphasized here and linked to the present understanding of the mechanism of a reaction that has sustained interest over the intervening years.

Synthesis and Properties of “Sandwich” Diimine-Coinage Metal Ethylene Complexes

“…Many processes, such as olefin polymerization, hydrogenation, metathesis, and cyclopropanation, involve the intermediacy of metal-alkene complexes. 1,2a The olefin complexes of group 11 metals are less common and become increasingly rare moving from copper to silver to gold despite their importance in cyclopropanation and carbon–hydrogen bond functionalization. 2 In fact, the first gold-ethylene complex was structurally characterized only recently.…”

Synthesis and applications of high-performance P-chiral phosphine ligands

“…Another attempted explanation was made by applying the Halpern–Brown mechanism, which is also known as the unsaturated mechanism, the major/minor concept, or the anti-lock-and-key mechanism. 109 – 117 ) However, not only the origin and the sense of the enantioselection but also the observed very high enantioselectivities could not be reasonably explained by the mechanism. These discrepancies are the main reasons why we initiated our mechanistic studies of the rhodium-catalyzed asymmetric hydrogenation.…”

Using chirality to probe the conformational dynamics and assembly of intrinsically disordered amyloid proteins

“…The importance of such intermediates has been recognized in the field of asymmetric catalysis, where species that are readily observed due to their thermodynamic stability may not represent catalytically active species. Reaction outcomes thus can be dictated by minor (sometimes undetectable) isomers 57 . Analogous behavior may be exhibited by aggregation-prone peptides as it relates to their toxicity.…”