Phosphite–oxazoline ligands for Rh-catalyzed asymmetric hydrosilylation of ketones

Pàmies, Òscar; Claver, Carmen; Diéguez, Montserrat

doi:10.1016/j.molcata.2006.01.019

Cited by 12 publications

(7 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unless stated otherwise, reactions were carried out under an atmosphere of nitrogen using standard Schlenk techniques. NMR spectra ( 1 H, 13 C, and 31 P) were measured on Bruker DRX 400 MHz and Bruker DRX 500 MHz instruments; CDCl 3 was used as a solvent, if not further specified.…”

Section: ■ Conclusionmentioning

confidence: 99%

“…1 H NMR (500 MHz, CDCl 3 ): δ 6.99 (s, 2H), 4.78 (s, 2H), 2.66 (m, 4H), 2.11 (m, 2H), 2.02 (m, 2H), 1.65 (m, 4H), 1.59 (m, 4H), 1.33 (s, 18H). 13 Synthesis of Compound (R)-9. 44 In a flame-dried Schlenk, distilled PCl 3 (0.21 mL, 2.46 mmol) and Et 3 N (0.70 mL, 4.92 mmol) were dissolved in dry toluene (22 mL).…”

Section: ■ Conclusionmentioning

confidence: 99%

“…Thus, phosphite-oxazoline ( S )- 5a (Figure ) constitutes one of the few examples of ligands that have provided high ee values in the Pd-catalyzed allylic alkylation of both the hindered model compound rac- ( E )-1,3-diphenyl-2-propenyl acetate ( S1 ) and unhindered cyclic substrate rac- 3-cyclohexenyl acetate ( S2 ) . This ligand has also been successfully applied in enantioselective palladium-catalyzed Heck reactions, rhodium-catalyzed hydrosilylation of ketones, and iridium-catalyzed hydroboration of 1,1-disubstituted olefins . Since the barrier to inversion in phosphite ligands is known to be lower than that in phosphepine and azepine ligands, we assumed that the broad substrate tolerance of ( S )- 5a may originate in its ability to adapt the conformation to the substrate undergoing reaction.…”

Section: Introductionmentioning

confidence: 99%

“…NMR spectra of (S)-8 and (R)-8, 1 H,13 C, and 31 P NMR spectra of 5b,c, 1 H and 31 P NMR spectra of 12−17, and computed structures and energies of Pd olefin complexes and transition states (PDF) ■ AUTHOR INFORMATION Corresponding Authors *E-mail for P.-O.N. : Per-Ola.Norrby@astrazeneca.com.…”

mentioning

confidence: 99%

“…J = 8.0 Hz, 3H), 0.82 (d, J = 8.0 Hz, 3H) 13. C NMR (101 MHz): δ 161.7 (CH), 150.8 (C), 145.3 (C), 144.9 (C), 139.0 (C), 138.6 (CH), 135.45 (CH), 135.47 (CH), 133.9 (CH), 133.2 (CH), 131.8 (C), 130.0 (CH), 128.1 (CH), 127.8 (CH), 124.2 (CH), 121.7 (C), 73.6 (CH 2 ), 70.7 (CH 2 ), 35.07 (CH), 35.05 (CH), 33.6 (CH 2 ), 31.5 (CH 3 ), 31.3 (CH 2 ), 30.2 (CH 2 ), 27.9 (CH 2 ), 23.51 (CH 2 ), 23.48 (CH 2 ), 23.47 (CH 2 ), 23.38 (CH 2 ), 23.35 (CH 2 ), 19.6 (CH 3 ), 18.7 (CH 3 ).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Conformational Preferences of a Tropos Biphenyl Phosphinooxazoline–a Ligand with Wide Substrate Scope

et al. 2016

Self Cite

View full text Add to dashboard Cite

Excellent enantioselectivities are observed in palladium-catalyzed allylic substitutions of a wide range of substrate types and nucleophiles using a bidentate ligand composed of oxazoline and chirally flexible biaryl phosphite elements. This unusually wide substrate scope is shown by experimental and theoretical studies of its η 3 -allyl and η 2 -olefin complexes not to be a result of configurational interconversion of the biaryl unit, since the ligand in all reactions adopts an S a ,S configuration on coordination to palladium, but rather the ability of the ligand to adapt the size of the substrate-binding pocket to the reacting substrate. This ability also serves as an explanation to its excellent performance in other types of catalytic processes.

show abstract

Section: ■ Conclusionmentioning

confidence: 99%

Section: ■ Conclusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Conformational Preferences of a Tropos Biphenyl Phosphinooxazoline–a Ligand with Wide Substrate Scope

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones

Schneider¹,

Finger²,

Haferkemper³

et al. 2009

Chemistry A European J

View full text Add to dashboard Cite

A detailed density functional theory (DFT) computational study (using the BP86/SV(P) and B3LYP/TZVP//BP86/SV(P) level of theory) of the rhodium-catalyzed hydrosilylation of ketones has shown three mechanistic pathways to be viable. They all involve the generation of a cationic complex [L(n)Rh(I)]+ stabilized by the coordination of two ketone molecules and the subsequent oxidative addition of the silane, which results in the Rh-silyl intermediates [L(n)Rh(III)(H)SiHMe2]+. However, they differ in the following reaction steps: in two of them, insertion of the ketone into the Rh-Si bond occurs, as previously proposed by Ojima et al., or into the Si-H bond, as proposed by Chan et al. for dihydrosilanes. The latter in particular is characterized by a very high activation barrier associated with the insertion of the ketone into the Si-H bond, thereby making a new, third mechanistic pathway that involves the formation of a silylene intermediate more likely. This "silylene mechanism" was found to have the lowest activation barrier for the rate-determining step, the migration of a rhodium-bonded hydride to the ketone that is coordinated to the silylene ligand. This explains the previously reported rate enhancement for R2SiH2 compared to R3SiH as well as the inverse kinetic isotope effect (KIE) observed experimentally for the overall catalytic cycle because deuterium prefers to be located in the stronger bond, that is, C-D versus M-D.

show abstract

Asymmetric Hydrosilylation of Unsaturated Carbon–Heteroatom Bonds

Marciniec

Advances in Silicon Science

View full text Add to dashboard Cite

Phosphite–oxazoline ligands for Rh-catalyzed asymmetric hydrosilylation of ketones

Cited by 12 publications

References 24 publications

Conformational Preferences of a Tropos Biphenyl Phosphinooxazoline–a Ligand with Wide Substrate Scope

Conformational Preferences of a Tropos Biphenyl Phosphinooxazoline–a Ligand with Wide Substrate Scope

Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones

Asymmetric Hydrosilylation of Unsaturated Carbon–Heteroatom Bonds

Contact Info

Product

Resources

About