New tagged naplephos ligands for asymmetric allylic substitutions under traditional and unconventional conditions

Benessere, Vincenzo; Lega, Matteo; Silipo, Alba; Ruffo, Francesco

doi:10.1016/j.tet.2011.05.013

Cited by 15 publications

(1 citation statement)

References 20 publications

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“…With the aim to better adapt the catalytic system to an ionic liquid medium, P-donor ligands with ionic moieties seem to stand for an appropriate approach. Actually, chiral P-based ligands containing a phosphate, ammonium, or imidazolium fragment have been conceived, but surprisingly just few of them have been used in asymmetric catalytic processes in IL medium such as in hydrogenation ,, and allylic substitution. ,, …”

Section: Introductionmentioning

confidence: 99%

Efficient Palladium Catalysts Containing Original Imidazolium-Tagged Chiral Diamidophosphite Ligands for Asymmetric Allylic Substitutions in Neat Ionic Liquid

et al. 2014

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New imidazolium-tagged chiral diamidophosphite ligands, (S,S)-a and (R)-b, derived from (S,S)-N,N′-dibenzyl-1,2-cyclohexanediamine and (R)-N,N′-dimethyl-1,1′-binaphthyl-2,2′-diamine, respectively, and the corresponding palladium allylic complexes of general formula [PdCl(η3-2-Me-C3H4)(κ1 P-L)]BF4 (1a,b) and [Pd(η3-2-Me-C3H4)(κ1 P-L)2](BF4)3 (2a,b) were synthesized and fully characterized, including the X-ray crystal structure for 1b. These original Pd/L catalytic systems were applied in asymmetric allylic alkylation, amination, and sulfonylation using rac-3-acetoxy-1,3-diphenyl-1-propene as a substrate in neat ionic liquids, [bmim][PF6] and [Pyr][NTf2]. The best results in terms of enantioselectivity were obtained with the catalytic precursor 1b in [Pyr][NTf2]. The catalytic phase containing 1b for the allylic amination could be recycled up to six times without significant loss of asymmetric induction.

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Section: Introductionmentioning

confidence: 99%

Efficient Palladium Catalysts Containing Original Imidazolium-Tagged Chiral Diamidophosphite Ligands for Asymmetric Allylic Substitutions in Neat Ionic Liquid

et al. 2014

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Ionic Liquids in Asymmetric Synthesis: An Overall View from Reaction Media to Supported Ionic Liquid Catalysis

et al. 2018

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Ionic liquids, as a special class of organic compounds, have attracted ever‐growing interest in recent years. They have been employed in many organic transformations as a green alternative to volatile organic solvents and as a catalyst to modify catalytic activity and recyclability. Recent developments have demonstrated that ionic liquids might also have many benefits in asymmetric reactions. In this review, we survey the use of ionic liquids in asymmetric transformations, including the use of ionic liquids as reaction media in asymmetric reactions, ionic‐liquid‐tagged chiral catalysts for use in asymmetric synthesis, and supported ionic liquid catalysts in asymmetric transformations.

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A New Modular Phosphite‐Pyridine Ligand Library for Asymmetric Pd‐Catalyzed Allylic Substitution Reactions: A Study of the Key Pd‐π‐Allyl Intermediates

Mazuela

Pàmies

Diéguez

2013

Chemistry A European J

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A library of phosphite-pyridine ligands L1-L12 a-g has been successfully applied for the first time in the Pd-catalyzed allylic substitution reactions of several di- and trisubstituted substrates by using a wide range of C, N and O nucleophiles, among which are the little studied α-substituted malonates, β-diketones, and alkyl alcohols. The highly modular nature of this ligand library enables the substituents/configuration at the ligand backbone, and the substituents/configurations at the biaryl phosphite moiety to be easily and systematically varied. We found that the introduction of an enantiopure biaryl phosphite moiety played an essential role in increasing the versatility of the Pd-catalytic systems. Enantioselectivities were therefore high for several hindered and unhindered di- and trisubstituted substrates by using a wide range of C, N and O nucleophiles. Of particular note were the high enantioselectivities (up to>99% ee) and high activities obtained for the trisubstituted substrates S6 and S7, which compare favorably with the best that have been reported in the literature. We have also extended the use of these new catalytic systems in alternative environmentally friendly solvents such as propylene carbonate and ionic liquids. Studies on the Pd-π-allyl intermediates provide a deeper understanding of the effect of ligand parameters on the origin of enantioselectivity.

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New tagged naplephos ligands for asymmetric allylic substitutions under traditional and unconventional conditions

Cited by 15 publications

References 20 publications

Efficient Palladium Catalysts Containing Original Imidazolium-Tagged Chiral Diamidophosphite Ligands for Asymmetric Allylic Substitutions in Neat Ionic Liquid

Efficient Palladium Catalysts Containing Original Imidazolium-Tagged Chiral Diamidophosphite Ligands for Asymmetric Allylic Substitutions in Neat Ionic Liquid

Ionic Liquids in Asymmetric Synthesis: An Overall View from Reaction Media to Supported Ionic Liquid Catalysis

A New Modular Phosphite‐Pyridine Ligand Library for Asymmetric Pd‐Catalyzed Allylic Substitution Reactions: A Study of the Key Pd‐π‐Allyl Intermediates

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