Investigation of the importance of nitrogen substituents in a N–P chiral ligand for enantioselective allylic alkylation

Anderson, James C.; Cubbon, Rachel; Harling, John D.

doi:10.1016/s0957-4166(01)00137-9

Cited by 42 publications

(16 citation statements)

References 37 publications

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“…The synthetic procedure for the complexes was reported in our previous articles. 21,22 The N-isopropyl amino acid 46 and N-phenyl amino acids 47 were synthesized based on literature procedures.…”

Section: Resultsmentioning

confidence: 99%

Twisted paddlewheel rhodium complexes: Contribution of central and axial chirality to ECD, VCD, and NMR spectra

et al. 2020

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Dirhodium complexes bearing N‐substituted chiral amino acid ligands are investigated. These complexes have an unusual twisted paddlewheel structure, showing inherent chirality. We would like to demonstrate that parallel application of chiroptical spectroscopic methods (ECD and VCD) and NMR spectroscopy combined with quantum chemical calculations constitutes a powerful tool to determine the configuration of the complexes unequivocally. Two chiroptical methods are needed to determine the absolute configuration: ECD for the coordinated nitrogen atom and VCD for the rhodium core. A quick to use NMR method is also presented: Upon the coordination of small molecules in the axial position, the relative configuration of both the rhodium core and the nitrogen atom can be determined simultaneously by studying spatial proximities provided by 1D NOE spectra.

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Section: Resultsmentioning

confidence: 99%

Twisted paddlewheel rhodium complexes: Contribution of central and axial chirality to ECD, VCD, and NMR spectra

et al. 2020

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“…As shown in scheme 1.31, Aderson and his coworkers reported the synthesis of chiral P,N-ligand 82 in five steps from the amino acid as the starting materials. [73] . Chiral P, N containing ligands 83 [74] and 84 [75] with two chiral carbon centers have been prepared from amino acid derivatives and tartaric acid respectively.…”

Section: A Chiral Pn-ligands Without P-heteroatom Bondmentioning

confidence: 99%

Application of palladacycle complexes in C-C, C-N and C-P bonds formation reactions

Chen¹

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“…ppm for the PF 6 À anion and two singlets at d = 41.32 and 41.23 ppm (for each diastereomer of 6) and at d = 39.4 and 39.0 ppm (for each diastereomer of 7). The integration of the N-methyl resonances in the 1 H NMR shows that both complexes 6 and 7 are formed without d.e.…”

Section: Separation Of the Diastereoisomersmentioning

confidence: 99%

“…As another example, the nature of the N-substituent of other aminophosphines chelates (S)-[Ph 2 CH 2 CH-( i Pr)NR 1 R 2 ] (with R 1 = Me or Ph and R 2 = Ph or i Pr) affects the enantioselectivity in palladium-catalysed allylic alkylation [6].…”

Section: Introductionmentioning

confidence: 99%

“…The different strategies are based either on the use of chiral amino-acids or L-valine [11][12][13] compound, or on the use of a chiral saturated N-heterocycle [14], or again on stereoselective additions to optically pure imines [15] or substituted aziridines [16]. These multistep syntheses lead to a single enantiomer of the similar ligands Ph 2 PCH 2 CH( i Pr)NPh 2 [12], Ph 2 PCH 2 CH( i Pr)NH i Pr and Ph 2 PCH 2 CH( i Pr)NH 2 [6] from L-valinol (derived from L-valine by reduction), with global yields between 17% and 25%. The access to both ligands L 1 and L 2 in an optically pure form in a shorter way than those mentioned above and/or by another higher yield procedure would be desirable for application to enantioselective catalytic processes.…”

Section: Introductionmentioning

confidence: 99%

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Resolution of β-aminophosphines with chiral cyclopalladated complexes

Camus

Garcı́a

Andrieu

et al. 2005

Journal of Organometallic Chemistry

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Resolution of the racemic chiral b-aminophosphines Ph 2 PCH 2 CH(Ph)NH(Ar) (L 1 for Ar = C 6 H 5 and L 2 for Ar = 2,6-C 6 H 3 i Pr 2 ) has been investigated by use of different cyclopalladated complexes as chiral agents. The resulting complexes afford diastereomeric adducts in a 1:1 ratio. After successive crystallizations from ethanol, a d.e. of 98% was achieved for one aminophosphine palladium complex, while no significant d.e. was obtained after crystallizations from chlorinated solvents. The X-ray structure analysis has pointed out intermolecular hydrogen interactions N-HÁ Á ÁCl between the P,N ligand and the chloride ion, which are responsible for the formation and stabilization of the diastereomeric adducts. Thus, the use of oxygenated solvents cancels such hydrogen interactions by their stronger donor character and makes the diastereomers separation possible, allowing to isolate the optically pure (R)-Ph 2 PCH 2 CH(Ph)NH(Ph) L 1 of which the absolute configuration has been determined from the X-ray structure analysis of the related palladium dichloride complex.

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Investigation of the importance of nitrogen substituents in a N–P chiral ligand for enantioselective allylic alkylation

Cited by 42 publications

References 37 publications

Twisted paddlewheel rhodium complexes: Contribution of central and axial chirality to ECD, VCD, and NMR spectra

Twisted paddlewheel rhodium complexes: Contribution of central and axial chirality to ECD, VCD, and NMR spectra

Application of palladacycle complexes in C-C, C-N and C-P bonds formation reactions

Resolution of β-aminophosphines with chiral cyclopalladated complexes

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