Recent developments in chiral anion mediated asymmetric chemistry

Lacour, Jérôme; Hebbe-Viton, Virginie

doi:10.1039/b205251m

Cited by 287 publications

(101 citation statements)

References 63 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…This prompted us to prepare a TRISPHAT salt for which no or little direct or induced circular dichroism could be expected from the cationic part of the salt, namely, the tetramethylammonium derivative, [Me 4 N] [1].…”

Section: Resultsmentioning

confidence: 99%

“…The ECD spectrum was then measured, and it matched our expectations as the positive and negative bands were again obtained for the exciton couplet in the p -p * region at lower and higher wavelengths, respectively (Dq 222 = À214, Dq 213 = +171); this result is in complete agreement with Mason's theory. 56 In Figure 3 are reported the UV and CD spectra of [Me 4 N] [1].…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2005

View full text Add to dashboard Cite

Herein is reported an experimental and theoretical study of the circular dichroism properties of TRISPHAT (1) anion. ECD analysis of the [tetramethylammonium][D-1] salt confirms the absolute configuration assignment obtained through X-ray crystallographic analysis of the parent cinchonidium salt. The structure, infrared, and vibrational circular dichroism (VCD) spectra derived from density functional theory (DFT) calculations are compared with experimental data. Chirality 17:S143 -S148, 2005.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Recently, highly efficient asymmetric catalyst systems based on chiral anions, [3] especially those with a binaphthyl backbone, have been reported to induce high levels of enantioselectivity. [4,5,6] List defined the concept as asymmetric counteranion-directed catalysis (ACDC) in a general strategy for asymmetric catalysis.…”

mentioning

confidence: 99%

Synergistic Effect: Hydroalkoxylation of Allenes through Combination of Enantiopure BIPHEP‐Gold Complexes and Chiral Anions

2010

View full text Add to dashboard Cite

A synergistic effect is observed for the combination of a neutral dinuclear gold complex with a chiral silver phosphate in the intramolecular hyroalkoxylation of allenes to give furan derivatives in high yields and enantioselectivities. The monocationic dinuclear gold complex affords higher catalytic activity and enantioselectivity than the neutral or dicationic digold complexes. The synergistic effect is thus highly promising to provide a guiding principle in designing an efficient chiral environment for creating an asymmetric catalyst.Keywords: asymmetric activation; chiral anion; chirality control; gold catalyst; hydroalkoxylation; synergistic effectRegarding new frontiers of asymmetric catalyst systems, a variety of highly efficient chiral ligands have been developed that dramatically increase the catalytic activity and enantioselectivity.[1] An asymmetric catalyst is usually constructed by a proper combination of chiral ligand and central metal. An asymmetric catalyst can be further evolved into a more activated catalyst to give higher catalytic activity and enantioselectivity with a chiral activator as an additional chiral source; for this process, we have previously coined the term asymmetric activation.[2] A synergistic effect has been observed where the matched pair with the additional chiral source (R or S) can lead to higher catalytic activity and enantioselectivity than the mismatched one (S or R).Recently, highly efficient asymmetric catalyst systems based on chiral anions, [3] especially those with a binaphthyl backbone, have been reported to induce high levels of enantioselectivity. [4,5,6] List defined the concept as asymmetric counteranion-directed catalysis (ACDC) in a general strategy for asymmetric catalysis.[5] The catalytic systems through the combination of chiral or achiral amines and chiral phosphate anions have been developed in transfer hydrogenation, [5a,b] allylation, [5c] and epoxidation [5d-f] with highto-excellent yield and enantioselectivity. As another important breakthrough, Toste and co-workers have also developed the chiral anion strategy for asymmetric transition metal catalysis for highly enantioselective hydroamination, [6] hydroalkoxylation, [6] and hydrocarboxylation [6a] reactions of allenic fragments by a gold catalyst bearing both chiral or achiral diphosphine ligand and chiral phosphate anion.On the other hand, we have found that the axial chirality of gold complexes bearing tropos BIPHEP ligands [BIPHEP = bis(phosphanyl)biphenyl], [7] which are highly modular, versatile, and easy to synthesize without enantiomer resolution, could be controlled by the phosphate and the corresponding N-triflyl phosphoramide as chiral anions (Scheme 1).[8] The axial chirality of BIPHEP-(AuCl) 2 complexes could also be memorized due to the Au À Au contact even after the dissociation of chiral anions. Treatment of the enantiopure BIPHEP-(AuCl) 2 complexes with two equivalents of Ag salt thus facilitated the intramolecular hydroamination of allenes as an atropos asymmetric...

show abstract

“…66 Its hexafluorophosphate salt was obtained in enantioenriched form (e.e. >96.4%) by ion pairing association with enantiopure BINPHAT anion, 67,68 selective precipitation of one diastereomeric salt (benzene/ THF), and ion metathesis with KPF 6 . Recently, a new and generally efficient protocol was reported for the resolution of cations 1 using (i) the addition of an enantiopure sulfoxide moiety, (ii) a facile chromatographic separation of the neutral diastereomers (DR f ¼ 0.3), and (iii) an unprecedented Pummerer fragmentation reaction; 69 the M and P enantiomers of 1 being then interesting precursors for the synthesis of inherently chiral pseudo-rotaxanes or powerful electrofugal leaving groups in fragmentationbased reactions.…”

Section: Introductionmentioning

confidence: 99%

Effective HPLC resolution of [4]heterohelicenium dyes on chiral stationary phases using reversed‐phase eluents

et al. 2006

View full text Add to dashboard Cite

[4]Heterohelicenium cations 1a-c adopt a twisted helical structure that renders them chiral. They are configurationally stable and their enantiomers have been resolved, for the first time, by HPLC on Chiralcel OD-RH and Chirobiotic TAG chiral stationary phases (CSPs). Chiral cations 1a-c have been resolved by HPLC using water-based eluents containing KPF(6) as additive. The elution order of the analyte enantiomers was determined by on-line CD detection, and was found to be opposite on the two CSPs. The effect of mobile phase composition and analyte structure on retention and enantioselectivity was investigated.

show abstract

Recent developments in chiral anion mediated asymmetric chemistry

Cited by 287 publications

References 63 publications

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

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

Synergistic Effect: Hydroalkoxylation of Allenes through Combination of Enantiopure BIPHEP‐Gold Complexes and Chiral Anions

Effective HPLC resolution of [4]heterohelicenium dyes on chiral stationary phases using reversed‐phase eluents

Contact Info

Product

Resources

About