Versatile Ligands for Palladium-Catalyzed Asymmetric Allylic Alkylation

Dierkes, Peter; Ramdeehul, Shailesh; Barloy, Laurent; Cian, André De; Fischer, Jean; Kamer, Paul C. J.; Leeuwen, Piet W. N. M. van; Osborn, John A.

doi:10.1002/(sici)1521-3773(19981204)37:22<3116::aid-anie3116>3.3.co;2-j

Cited by 23 publications

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“…The overall structure of 11 is very close to the reported structure of [Pd{( R , R )‐Duthixantphospholane}(cyclohexenyl)] + 4a. The conformational characteristics of the Duxantphos ligand in complex 11 are similar to those of achiral xanthene‐based ligands coordinated to palladium 15,16.…”

Section: Resultssupporting

confidence: 65%

Palladium Complexes with Chiral Diphospholane Ligands: Comparative Catalytic Properties and Analysis of (η³‐Allyl)palladium Species

et al. 2004

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The chiral diphospholane ligands Duphos (1) and Duxantphos (2), which can be differentiated by their bite angle, were applied to palladium-catalysed asymmetric reactions, essentially allylic alkylations with symmetrically (3a−d) or unsymmetrically (5a,b) substituted allylic acetates as substrates. The most interesting results were found with the first series of substrates in which 2 was more reactive and/or selective than 1. The model complexes of the catalytic intermediates [Pd{(S,S)-1}(η 3 -cyclohexenyl)](BF 4 ) (10) and exo-[Pd{(R,R)-2}(η 3 -cyclohexenyl)](SbF 6 ) (11) could be characterised by X-ray crystallography.

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Section: Resultssupporting

confidence: 65%

Palladium Complexes with Chiral Diphospholane Ligands: Comparative Catalytic Properties and Analysis of (η³‐Allyl)palladium Species

et al. 2004

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“…Recently, chiral variants of Xantphos ligands were reported [35] containing phospholane groups as introduced by Burk in DUPHOS ligands [36]. The new DuXantphos ligands turned out to be very versatile, giving high enantiomeric excesses in many reactions including kinetic resolution of O-acetylcyclohex-2 enol (Scheme 5).…”

Section: Methodsmentioning

confidence: 99%

The bite angle makes the catalyst

Leeuwen¹,

Kamer²,

Reek³

1999

Pure and Applied Chemistry

109

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Catalytic reactions are described for metal complexes containing bidentate phosphine ligands that enforce wide bite angles in the complexes. The calculated natural bite angles are in the range 100±1208. Three applications will be discussed: (i) nickel catalysed hydrocyanation, for which the ®rst active phosphine catalyst was found, (ii) palladium catalysed allylic alkylation, for which the selectivity also strongly depends on the bite angle, and (iii) rhodium catalysed hydroformylation, which leads to highly linear products.

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“…As the chirality with the DuPhos ligands is within the phospholane rings, a wide variety of backbones can be used ranging from ferrocene to heterocycles [61,62,77,222,[251][252][253][254][255][256][257][258][259][260][261][262].…”

Section: Duphosmentioning

confidence: 99%

Enantioselective Alkene Hydrogenation: Introduction and Historic Overview

Ager¹

2006

The Handbook of Homogeneous Hydrogenation

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23Enantioselective Alkene Hydrogenation: Introduction and Historic Overview Development of CAMP and DIPAMPDuring the late 1960s, Horner et al. [13] and Knowles and Sabacky [14] independently found that a chiral monodentate tertiary phosphine, in the presence of a rhodium complex, could provide enantioselective induction for a hydrogenation, although the amount of induction was small [15][16][17][18][19][20]. The chiral phosphine ligand replaced the triphenylphosphine in a Wilkinson-type catalyst [10,21,22]. At about this time, it was also found that [Rh(COD) 2 ] + or [Rh(NBD) 2 ] + could be used as catalyst precursors, without the need to perform ligand exchange reactions [23].Knowles found that the monophosphine CAMP (1a) could provide an ee-value of up to 88% for the reduction of dehydroamino acids. CAMP was an extension of PAMP (1b) that provides ee-values of 50-60% in analogous reactions [24]. At this time, Kagan showed that DIOP (2) (vide infra), where the stereogenic centers are not at phosphorus, could also provide enantioselective induction in an hydrogenation. DIOP also showed that a bisphosphine need not have the chirality at phosphorus, and that good stereoselectivity might result from a C 2 -symmetric ligand. Knowles then developed the C 2 -symmetric ligand DIPAMP (3) [22,25]. The use of Rh-DIPAMP for the synthesis of l-Dopa is well known and is still practiced today [12,22,27]. A number of variations of the DIPAMP structure were investigated for the synthesis of this important pharmaceutical, but the parent remains the best ligand in this class [22].

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Versatile Ligands for Palladium-Catalyzed Asymmetric Allylic Alkylation

Cited by 23 publications

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Palladium Complexes with Chiral Diphospholane Ligands: Comparative Catalytic Properties and Analysis of (η³‐Allyl)palladium Species

Palladium Complexes with Chiral Diphospholane Ligands: Comparative Catalytic Properties and Analysis of (η³‐Allyl)palladium Species

The bite angle makes the catalyst

Enantioselective Alkene Hydrogenation: Introduction and Historic Overview

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Versatile Ligands for Palladium-Catalyzed Asymmetric Allylic Alkylation

Cited by 23 publications

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Palladium Complexes with Chiral Diphospholane Ligands: Comparative Catalytic Properties and Analysis of (η3‐Allyl)palladium Species

Palladium Complexes with Chiral Diphospholane Ligands: Comparative Catalytic Properties and Analysis of (η3‐Allyl)palladium Species

The bite angle makes the catalyst

Enantioselective Alkene Hydrogenation: Introduction and Historic Overview

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Palladium Complexes with Chiral Diphospholane Ligands: Comparative Catalytic Properties and Analysis of (η³‐Allyl)palladium Species

Palladium Complexes with Chiral Diphospholane Ligands: Comparative Catalytic Properties and Analysis of (η³‐Allyl)palladium Species