Catechol-Based Phosphoramidites:  A New Class of Chiral Ligands for Rhodium-Catalyzed Asymmetric Hydrogenations

Hoen, Rob; Berg, Michel van den; Bernsmann, Heiko; Minnaard, Adriaan J.; Vries, Johannes G. de; Feringa, Bernard

doi:10.1021/ol049726g

Cited by 95 publications

(39 citation statements)

References 40 publications

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“…EI mass spectrum: m/z 376 (M + ). 31 22) were observed for the diastereoisomeric product formed when the S-enantiomer was used.…”

Section: Methodsmentioning

confidence: 93%

“…22 Retention times for the products from substrate D were 11.08 and 11.27 min, from substrate E were 37.50 and 38.10 min, from substrate F were 5.1 and 5.5 min, from substrate G were 6.3 and 6.6 min and from substrate H were 22 and 27 min. The analysis is hampered by the presence of a local near-centre of symmetry between the two independent molecules in the P1 unit cell.…”

Section: Preparation Of [Rh(norbornadiene)(1a)][bf 4 ] (3a)mentioning

confidence: 96%

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Efficient asymmetric hydrogenation with rhodium complexes of C1-symmetric 2,5-dimethylphospholane-diphenylphosphines

et al. 2004

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Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. . The crystal structure of 2a reveals that only one quadrant is blocked. Asymmetric hydrogenation of acrylic esters and enamides using 3a and 3b as catalysts show that the phenylene-backboned diphosphine gives a more efficient catalyst in terms of asymmetric induction than the more flexible ferrocene-backboned diphosphine.The best results, which were obtained with 3a and enamide substrates, exceeded those obtained with Duphos catalysts. The rate of hydrogenation of the enamides with 3a was 10 times faster than with [Rh(Duphos)(diene)][BF 4 ]. A quadrant diagram can be used to predict the configuration of the major product, provided it is assumed to be derived from the less sterically congested intermediate.

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“…EI mass spectrum: m/z 376 (M + ). 31 22) were observed for the diastereoisomeric product formed when the S-enantiomer was used.…”

Section: Methodsmentioning

confidence: 93%

Section: Preparation Of [Rh(norbornadiene)(1a)][bf 4 ] (3a)mentioning

confidence: 96%

Efficient asymmetric hydrogenation with rhodium complexes of C1-symmetric 2,5-dimethylphospholane-diphenylphosphines

et al. 2004

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“…The results achieved with P*-chiral diamidophosphite (R,S,R a )-2 are rather remarkable, as there are only a few examples in asym- metric hydrogenation when P monodentate phosphite-type ligands without BINOL and biphenol moieties showed satisfactory enantioselectivity. [46][47][48][49] …”

Section: Rhodium-catalysed Asymmetric Hydrogenationmentioning

confidence: 99%

MOP‐Type Binaphthyl Phosphite and Diamidophosphite Ligands and Their Application in Catalytic Asymmetric Transformations

et al. 2007

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Monodentate phosphite and diamidophosphite ligands have been developed based on Omethyl-BINOL. These chiral ligands are easy to prepare from readily accessible phosphorylating re-The new ligands have demonstrated excellent enantioselectivity in the palladium-catalysed allylic substitution reactions of (E)-1,3-diphenylallyl acetate with sodium p-toluenesulfinate (up to 99 % ee), pyrrolidine (up to 97 % ee), dipropylamine (up to 95 % ee) and dimethyl malonate (up to 99 % ee). In the palladium-catalysed deracemization of ethyl (E)-1,3-diphenylallyl carbonate, up to 96 % enantioselectivity has been achieved. The diamidophosphite ligands have exhibited very good enantioselectivity in the Rh-catalysed asymmetric hydrogenation of dimethyl itaconate (up to 90 % ee).

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“…[21] Next, we tested three bidentate phosphoramidite ligands (entries 2-4). Again, slow reactions ensued and the enantioselectivities ranged from low to moderate.…”

Section: Resultsmentioning

confidence: 99%

Ruthenium‐Catalysed Hydrogenation of Aromatic Ketones using Monodentate Phosphoramidite Ligands

et al. 2010

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A ruthenium pre-catalyst containing two equivalents of the bulky monodentate phosphoramidite 3,3'-dimethyl-PipPhos and one equivalent of a chiral diamine such as 1,2-diphenylethylenediamine or 1,2-diaminocyclohexane was used for the asymmetric hydrogenation of aromatic ketones. A range of substituted and unsubstituted aryl alkyl ketones was hydrogenated using only 0.1 mol% of this catalyst with full conversions and enantioselectivities up to 97%. The phosphoramidite and diamine ligands matched when both had the same configuration, i.e., S-phosphoramidite with S,S-diamine. In that case the product was obtained with high enantioselectivity and the R-configuration. The mismatched case produced the product in lower ee. The product configuration was determined by the configuration of the diamine ligand. A mechanistic proposal was made.

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Catechol-Based Phosphoramidites: A New Class of Chiral Ligands for Rhodium-Catalyzed Asymmetric Hydrogenations

Abstract: [reaction: see text] The synthesis and application of a new class of catechol-based phosphoramidites is described. Ees up to 99% were obtained in the rhodium-catalyzed asymmetric hydrogenation of dehydroamino acids and enamides.

Cited by 95 publications

References 40 publications

Efficient asymmetric hydrogenation with rhodium complexes of C1-symmetric 2,5-dimethylphospholane-diphenylphosphines

Efficient asymmetric hydrogenation with rhodium complexes of C1-symmetric 2,5-dimethylphospholane-diphenylphosphines

MOP‐Type Binaphthyl Phosphite and Diamidophosphite Ligands and Their Application in Catalytic Asymmetric Transformations

Ruthenium‐Catalysed Hydrogenation of Aromatic Ketones using Monodentate Phosphoramidite Ligands

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