Vibrational and electronic circular dichroism of Δ-TRISPHAT [tris(tetrachlorobenzenediolato)phosphate(V)] anion

Bas, Delphine; Bürgi, Thomas; Lacour, Jérôme; Vachon, Jérôme; Weber, Jacques

doi:10.1002/chir.20131

Cited by 23 publications

(15 citation statements)

References 63 publications

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“…(−)‐[ 5 ][ Δ ‐ 4 a ], Figure 2) showed an absolute Δ configuration for 4 a and 4 b 13. 14 The PO bond lengths and O‐P‐O bond angles are virtually identical to those measured for TRISPHAT 1 . The nonracemic anions 4 a and 4 b displayed good chemical and configurational stability, as no evidence of a racemization could be found, for instance, during the ion‐exchange metathesis of cation 5 by Bu 4 N + .…”

Section: Methodssupporting

confidence: 59%

Fluorinated TRISPHAT Anions: Spectroscopic Probes for Detailed Asymmetric Ion Pairing Studies

et al. 2005

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Placing fluorine atoms at selected positions allows enantiopure hexacoordinate phosphate anions to behave as effective chiral solvating and resolving agents for RuII complexes (the structure of one of the anions is shown: F: yellow; O: red; Cl: green; P: purple). The structural features of the asymmetric ion pairing can be determined by NMR spectroscopy owing to the presence of the fluorine atoms.Fluoratome an ausgewählten Positionen machen enantiomerenreine hexakoordinierte Phosphatanionen zu effektiven chiralen solvatisierenden und trennenden Agentien für RuII-Komplexe (die Struktur eines Anions ist gezeigt: F: gelb; O: rot; Cl: grün; P: violett). Die Strukturmerkmale der asymmetrischen Ionenpaarung können wegen der Fluoratome NMR-spektroskopisch bestimmt werden

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Section: Methodssupporting

confidence: 59%

Fluorinated TRISPHAT Anions: Spectroscopic Probes for Detailed Asymmetric Ion Pairing Studies

et al. 2005

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“…Fori nstance,c hiral oxiranes in water were found to induce aVCD signal for the H 2 Obending modes, [14] and more recently,a mmonia was shown to become optically active upon interacting with methyl lactate under matrixisolation conditions. [15] Furthermore,chiral induction in an ion pair has been reported by Bas et al [16] This encouraged us to apply VCD spectroscopy to study chirality-induction phenomena in ion-pair-based asymmetric catalysis with the focus on establishing structure-spectra relationships which can be used to predict catalytic selectivity.…”

mentioning

confidence: 95%

Stereochemical Communication within a Chiral Ion Pair Catalyst

et al. 2015

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Ionic interactions are increasingly appreciated as a key, asymmetry-inducing factor in enantioselective catalytic transformations, including those involving Brønsted acid or base catalysis, phase-transfer catalysis, and related processes. However, a detailed understanding of these interactions is often lacking. Herein, we show how an enantiopure anion enforces a chiral conformation onto a catalytically relevant achiral cation. Specifically, we use vibrational circular dichroism (VCD) spectroscopy to monitor the transmission of stereochemical information from a chiral phosphate anion to a flexible manganese(III)-salen cation. We show that VCD can be used to study solvent effects and that the obtained chiroptical data directly and quantitatively correlate with the experimentally observed enantioselectivity in an asymmetric olefin epoxidation reaction.

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“…54 PÀ ÀO bond lengths and OÀ ÀPÀ ÀO bond angles are similar to those measured for TRISPHAT 1 and BINPHAT 2, 4,7 with the two PÀ ÀO bonds linked to the carbohydrate unit being shorter ($1.67 Å ) than the others ($1.74 Å ). The configurational assignment was further established in solution by circular dichroism (CD) analysis of salt (1) 62 Diols 5 and 6 were then used in the aforementioned protocol. However, in these two cases, the synthesis of the resulting phosphate anions was unselective.…”

Section: Results and Discussion Ligand Selection And Synthesis Of Sugmentioning

confidence: 99%

Sugar derived hexacoordinated phosphates: Chiral anionic auxiliaries with general asymmetric efficiency

Pérollier¹,

Bérnardinelli²,

Lacour³

2007

Chirality

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Mannose-derived hexacoordinated phosphate anions, prepared in as few as two steps from methyl-alpha-D-mannopyranoside and tris(dimethylamino)phosphine, are chiral anionic auxiliaries with broad asymmetric efficiency. These chemically robust anions are effective NMR chiral solvating agents and efficient asymmetry-inducers, able to control the configuration of conformationally labile C2-symmetric monomethinium cations (organic, helical, charge 1+, P or M enantiomers) and D3-symmetric iron(II) trisdiimine complexes (metallo-organic, octahedral, charge 2+, Delta or Lambda enantiomers). Diastereomeric control with often unmatched selective levels was achieved with the help of mannopyranoside backbone of the anions and the substituents on the [1,3]dioxane ring that play a key role in the recognition process, something not obvious at first sight.

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Vibrational and electronic circular dichroism of Δ-TRISPHAT [tris(tetrachlorobenzenediolato)phosphate(V)] anion

Cited by 23 publications

References 63 publications

Fluorinated TRISPHAT Anions: Spectroscopic Probes for Detailed Asymmetric Ion Pairing Studies

Fluorinated TRISPHAT Anions: Spectroscopic Probes for Detailed Asymmetric Ion Pairing Studies

Stereochemical Communication within a Chiral Ion Pair Catalyst

Sugar derived hexacoordinated phosphates: Chiral anionic auxiliaries with general asymmetric efficiency

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