BINOL-derived phosphoramidites in asymmetric hydrogenation: can the presence of a functionality in the amino group influence the catalytic outcome?

Abstract

In discovering the remarkable catalytic properties of BINOL-derived phosphoramidites (binoP-NR(2)), Dutch researchers recently achieved a long-awaited breakthrough in asymmetric catalysis. For the first time, easily accessible monodentate chiral P(III) ligands turned out to provide high enantioselectivities when used in rhodium-catalysed olefin hydrogenation. The simplest ligand representative of this family is MonoPhos, which can be made straightforwardly from BINOL and hexamethylphosphorous triamide. Since the first publication dealing with such catalysts (J. Am. Chem. Soc., 2000), a variety of binoP-NRR' ligands have been reported in which the amino group bears a functional substituent or a stereogenic centre. This critical review examines the impact of the presence of such a functionality in the amino group on catalytic olefin hydrogenation reactions.

Secondary Interactions or Ligand Scrambling? Subtle Steric Effects Govern the Iridium(I) Coordination Chemistry of Phosphoramidite Ligands

“…[2][3][4] Also, the substituents at the nitrogen atom have been recognized to be noninnocent, but their effects are poorly understood. [5] For instance, the unlike and like diastereomeric ligands (aR,S,S)-1 a and (aR,R,R)-1 a' show widely differing influences in the iridium(I)-catalyzed asymmetric allylic alkylation of allylic acetates, [6] as well as in the rhodium(I)-catalyzed asymmetric [5+2] cycloaddition of alkyne-vinylcyclopropanes. [7] Abstract: The like and unlike isomers of phosphoramidite (P*) ligands are found to react differently with iridium(I), which is a key to explaining the apparently inconsistent results obtained by us and other research groups in a variety of catalytic reactions.…”

Amino Acid Based Phosphoramidite Ligands for the Rhodium‐Catalyzed Asymmetric Hydrogenation

“…In addition, the functional groups can be utilized for formation of supramolecular ligands [7] or for substrate orientation via supramolecular interactions between substrates and ligands. [8] Surprisingly, there has been no systematic investigation on the use of phosphoramidite ligands derived from α-amino acids [9] and they have only been scarcely used in catalysis. [10] Herein, we report the straightforward synthesis of monodentate phosphoramidite ligands derived from cheap and readily available α-amino acid derivatives.…”

Under Pressure: Rapid Development of Scalable Asymmetric Hydrogenation Catalysts

“…Thus, we decided to focus on the development of simple ligands that can be synthesized in 1-2 synthetic steps from readily available chiral starting materials. In collaboration with the groups of de Vries, Feringa and Minnaard at the University of Groningen, we have pioneered the use of monodentate BINOL-based phosphoramidites as ligands for asymmetric hydrogenation [8][9][10][11].…”