Enantiocontrol in the intermolecular cyclopropanation reaction catalyzed by dirhodium(ii) complexes with ortho-metalated aryl phosphine ligands

Barberis, Mario; Lahuerta, Pascual; Pérez‐Prieto, Julia; Sanaú, Mercedes

doi:10.1039/b010145c

Cited by 38 publications

(27 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dirhodium compounds containing two ortho ‐metalated aryl phosphine (PC) groups show high activity and chemoselectivity in the catalytic transformation of α‐diazocarbonyl compounds,24–26 and have been exploited for enantioselective reactions 25. 27–29 Related compounds with chiral phospholanes have also been tested as enantioselective catalysts 30. 31 In addition, heterogeneous dinuclear rhodium(II) compounds are active for hydroformylation reactions 32…”

Section: Introductionmentioning

confidence: 99%

Dirhodium(II) Compounds with Bridging Thienylphosphines: Studies on Reversible P,C/P,S Coordination

Lloret‐Fillol

Estevan

Lahuerta

et al. 2009

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Monocyclometalated compound [Rh(2){(C(8)H(4)S)P(C(8)H(5)S)(2)}(CH(3)CO(2)H)(2)(O(2)CCH(3))(3)] (1 a) and bis-cyclometalated compound [Rh(2){(C(8)H(4)S)P(C(8)H(5)S)(2)}(2)(CH(3)CO(2)H)(2)(O(2)CCH(3))(2)] (2 a) have been isolated from the reaction of dirhodium tetraacetate and tris(2-benzo[b]thienyl)phosphine (2 BTP) using low acidic solutions. By contrast, in pure acetic acid the reaction of Rh(2)(O(2)CCH(3))(4) with 2 BTP and tris(2-thienyl)phosphine (2 TP), followed by replacement of the axial acetate ligands by chlorides, led to [Rh(2){(2-C(8)H(5)S)P(2-C(8)H(5)S)(2)}(2)Cl(2)(O(2)CCH(3))(2)] (3 b) and [Rh(2){(2-C(4)H(3)S)P(C(4)H(3)S)(2)}(2)Cl(2)(O(2)CCH(3))(2)] (5 b), respectively. These new dirhodium(II) compounds possess equatorial bridging ligands in a phosphorous-sulfur (P,S) coordination mode. The reversible switching between the P,C and P,S bonding mode of the phosphine has been studied in the monocyclometalated [Rh(2){(C(4)H(2)S)P(C(4)H(3)S)(2)}(CH(3)CO(2)H)(2)(O(2)CCH(3))(3)] (6 a), which was selectively transformed into compound [Rh(2){(2-C(4)H(3)S)P(C(4)H(3)S)(2)}(CF(3)SO(3))(CH(3)CO(2)H)(O(2)CCH(3))(3)] (7 c) in triflic acid media. Remarkably, compound 7 c reverts to the starting compound 6 a upon treatment with sodium acetate. Theoretical DFT calculations for both the P,C/P,S rearrangement and the base-promoted reversion have been performed to explain the experimental findings. Data suggest the P,C/P,S rearrangement occurs by means of a "concerted protonation-demetalation mechanism" followed by eta(2) coordination of the thienyl ring and subsequent isomerization to the S-eta(1)-coordination mode. In the reversion reaction, the base coordinated at the axial position would promote a concerted metalation-deprotonation mechanism.

show abstract

Section: Introductionmentioning

confidence: 99%

Dirhodium(II) Compounds with Bridging Thienylphosphines: Studies on Reversible P,C/P,S Coordination

Lloret‐Fillol

Estevan

Lahuerta

et al. 2009

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

show abstract

“…57 This was anticipated as EDA generally gives low diastereoselectivities in Rh II -carbene cyclopropanation reactions. [58][59][60] Cyclic voltammetry experiments were performed to probe the effect of the tethered thioether ligands on the electronics at the Rh metal centers. Early studies demonstrated that the variance of the Rh 4+ /Rh 5+ oxidation potential could be used as a metric for the strength of axial coordination.…”

Section: Resultsmentioning

confidence: 99%

Tuning Rh(II)-Catalyzed Cyclopropanation with Tethered Thioether Ligands

Cressy¹,

Zavala²,

Abshire³

et al. 2020

Preprint

View full text Add to dashboard Cite

Dirhodium(II) paddlewheel complexes have high utility in diazo-mediated cyclopropanation reactions and ethyl diazoacetate is one of the most commonly used diazo compounds in this reaction. In this study, we report our efforts to use tethered thioether ligands to tune the reactivity of Rh-carbene mediated cyclopropanation of olefins with ethyl diazoacetate. Microwave methods enabled the synthesis of a family of Rh-complexes in which tethered thioether moieties were coordinated to axial sites of the complex. Different tether lengths and thioether substituents were screened to optimize cyclopropane yeilds and minimize side product formation. Furthermore, good yields were obtained when equimolar diazo and olefin were used. Structural and spectroscopic investigation revealed that tethered thioethers changed the electronic structure of the rhodium core, which was instrumental in the performance of the catalysts. Computational modeling of the catalysts provided further support that the tethered thioethers were responsible for increased yields.

show abstract

“…The results obtained in the cyclopropanation of styrene with ethyl diazoacetate using compounds 6a and 6b deserve a comparison with those reported for related dirhodium (II) catalysts containing triphenylphosphine and other p-substituted arylphosphines of formula Rh(O 2 CCF 3 ) 2 [(4-XC 6 H 3 )P(4-XC 6 H 4 ) 2 ] 2 [8], (X = H, CH 3 , F). The observed yields 60-70% (Table 1), are among the highest reported for these cyclometalated dirhodium (II) compound.…”

Section: Intermolecular Cyclopropanationmentioning

confidence: 88%

“…They are a family of dirhodium (II) compounds and show good activity and selectivity in the catalytic transformation of a-diazocarbonyl compounds. The inherent backbone chirality of these compounds has been explored for enantioselective reactions [8][9][10][11][12] since the racemic mixture can be separated by standard resolution methods in the M and P enantiomers [11,13].…”

Section: Introductionmentioning

confidence: 99%

Rhodium (II) compounds with functionalized metalated phosphines as bridging ligands

Estevan

Lahuerta

Lloret‐Fillol

et al. 2005

Journal of Organometallic Chemistry

View full text Add to dashboard Cite

Enantiocontrol in the intermolecular cyclopropanation reaction catalyzed by dirhodium(ii) complexes with ortho-metalated aryl phosphine ligands

Cited by 38 publications

References 15 publications

Dirhodium(II) Compounds with Bridging Thienylphosphines: Studies on Reversible P,C/P,S Coordination

Dirhodium(II) Compounds with Bridging Thienylphosphines: Studies on Reversible P,C/P,S Coordination

Tuning Rh(II)-Catalyzed Cyclopropanation with Tethered Thioether Ligands

Rhodium (II) compounds with functionalized metalated phosphines as bridging ligands

Contact Info

Product

Resources

About