Enantiopure bisphosphine ligands with appended crown ether groups as regulation sites for Rh-mediated hydrogenations

Fernández‐Pérez, Héctor; Mon, Ignasi; Frontera, Antonio; Vidal‐Ferran, Anton

doi:10.1016/j.tet.2015.02.073

Cited by 24 publications

(10 citation statements)

References 20 publications

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“…Within the supramolecular enantioselective catalysis arena, progress has been made in regulating the size and shape of the chiral catalyst, or in modifying the first-sphere coordination geometry of the active metal . However, there are few examples of fine modification of the geometry of the active site that do not imply major alteration of the principal structural features of the enantioselective catalyst. , …”

Section: Introductionmentioning

confidence: 99%

Palladium-Based Supramolecularly Regulated Catalysts for Asymmetric Allylic Substitutions

2016

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ABSTRACT:Herein is reported the effect of different polyether binders (alkali metal, alkaline earth metal and lanthanide salts) as regulation agents to enhance the catalytic properties of palladium complexes derived from enantiopure bisphosphite ligands in allylic substitutions. ) led to positive effects in enantioselectivity (by up to 16% ee) for the allylic substitution reactions. These ligands coordinated in the usual cis-fashion or in an unprecedented transfashion to the palladium center, depending on the phosphite group, and presented different reactivity in the allylic substitutions.

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Section: Introductionmentioning

confidence: 99%

Palladium-Based Supramolecularly Regulated Catalysts for Asymmetric Allylic Substitutions

2016

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“…Self‐assembly ligand systems have also been used successfully in asymmetric catalysis, and the necessary asymmetric induction has so far been achieved using building blocks with either chiral P ‐donors or an axially chiral biphenyl moiety as a stereoregulating unit . The groups of Raynal and Vidal‐Ferran achieved stereocontrol through the co‐assembly of chiral benzene‐1,3,5‐tricarboxamides (BTA) with achiral BTAs functionalized with P ‐donor moieties in a helical scaffold .…”

Section: Methodsmentioning

confidence: 99%

“…[17,18] In this manner, ab y-design nonlinear amplification of stereoselectivity was achieved.Self-assembly ligand systems have also been used successfully in asymmetric catalysis, [19] and the necessary asymmetric induction has so far been achieved using building blocks with either chiral P-donors [20][21][22][23] or an axially chiral biphenyl moiety as as tereoregulating unit. [24] Theg roups of Raynal and Vidal-Ferran achieved stereocontrol through the coassembly of chiral benzene-1,3,5-tricarboxamides (BTA) with achiral BTAs functionalized with P-donor moieties in ahelical scaffold. [25,26] Theg roup of Reek demonstrated that stereocontrol in asupramolecular catalyst system could be achieved by either entrapment of the rhodium center in asupramolecular metallocage [27] or by molecular recognition of ac hiral cofactor in ab identate ligand.…”

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confidence: 99%

Inducing Axial Chirality in a Supramolecular Catalyst

2018

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A new type of ligand, which is able to form axially chiral, supramolecular complexes was designed using DFT calculations. Two chiral monomers, each featuring a covalently bound chiral auxiliary, form a bidentate phosphine ligand with a twisted, hydrogen-bonded backbone upon coordination to a transition metal center which results in two diastereomeric, tropos complexes. The ratio of the diastereomers in solution is very temperature- and solvent-dependent. Rhodium and platinum complexes were analyzed through a combination of NMR studies, ESI-MS measurements, as well as UV-VIS and circular dichroism spectroscopy. The chiral self-organized ligands were evaluated in the rhodium-catalyzed asymmetric hydrogenation of α-dehydrogenated amino acids and resulted in good conversion and high enantioselectivity. This research opens the way for new ligand designs based on stereocontrol of supramolecular assemblies through stereodirecting chiral centers.

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“…Vidal-Ferran et al reported the preparation of bisphosphine ligand L2, which incorporates a crown-ether motif as a regulation site, and its use in rhodium-mediated asymmetric hydrogenations (AHs). 17 The authors envisaged that binding a regulation agent to the crown-ether motif could modulate the catalyst performance by modifying the dihedral angle  of the biaryl unit (see Fig. 2a for a general representation of the regulation principle).…”

Section: Supramolecular Regulation On An Already Formed Enantioselectmentioning

confidence: 99%

Supramolecularly fine-regulated enantioselective catalysts

2016

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The use of supramolecular interactions in catalysis has undergone major growth in the last decade and has contributed to the major advances achieved in the field of enantioselective catalysis. Of the various approaches that use supramolecular interactions in enantioselective catalysis, this article highlights different supramolecular strategies to generate a set of enantiopure ligands (or enantioselective catalysts) that retain the majority of the backbone's structural features, yet at the same time incorporate subtle changes at its active site that depend on the structural characteristics of the regulation agent (RA) employed.

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Enantiopure bisphosphine ligands with appended crown ether groups as regulation sites for Rh-mediated hydrogenations

Cited by 24 publications

References 20 publications

Palladium-Based Supramolecularly Regulated Catalysts for Asymmetric Allylic Substitutions

Palladium-Based Supramolecularly Regulated Catalysts for Asymmetric Allylic Substitutions

Inducing Axial Chirality in a Supramolecular Catalyst

Supramolecularly fine-regulated enantioselective catalysts

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