A first approach to asymmetric protonation via a polymer supported chiral proton donor

Cavelier, Florine; Gomez, Sylvie; Jacquier, Robert; Verducci, Jean

doi:10.1016/s0040-4039(00)76652-4

Cited by 37 publications

(6 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the enantioselective protonation of enolates occurs under kinetic control, it appears that there is a temperature threshold (around –50 °C) above which efficient proton transfer takes place. This apparent paradoxical effect of temperature in enantioselective protonation has been reported previously by us14c and by others 20. Finally, a different sulfinyl alcohol 1b was tested, but the ee could not be improved (Table 1, entry 22) because of its low solubility under our reaction conditions.…”

Section: Resultssupporting

confidence: 54%

Enantioselective Protonation of the Lithium Transient Enolate of2‐Methyltetralone with 2‐Sulfinyl Alcohols

et al. 2005

View full text Add to dashboard Cite

A new catalytic cycle for the enantioselective protonation of cyclic ketone enolates with sulfinyl alcohols has been developed. An enol trifluoroacetate that can be easily obtained from the corresponding ketone is used for the first time as an enolate precursor of a cyclic ketone enolate. In this method, the achiral alcohol plays two roles: it is involved, as is usual in catalytic asymmetric protonation reactions, in the turnover of the chiral proton source and also in the generation of a

show abstract

Section: Resultssupporting

confidence: 54%

Enantioselective Protonation of the Lithium Transient Enolate of2‐Methyltetralone with 2‐Sulfinyl Alcohols

et al. 2005

View full text Add to dashboard Cite

show abstract

“…The increase in enantioselectivity with an increase in the temperature of protonations with alcohol ( S , Rs )- 2c is not common in the field of enantioselective protonation. In fact, there is only one precedent in the literature concerning the protonation of a silyl enol ether by mandelic acid bound to a polymeric resin . The authors of that report explained their result on the basis of a two-step mechanism involving the preliminary formation of rapidly interconverting diastereomeric complexes.…”

Section: Resultsmentioning

confidence: 99%

Stereoselection Parameters and Theoretical Model in the Enantioselective Protonation of Enolates with α-Sulfinyl Alcohols

Asensio¹,

Alemán²,

Gil³

et al. 1998

J. Org. Chem.

View full text Add to dashboard Cite

The effects of the solvent, temperature, presence of lithium salts in the medium, and acidity of the proton source on enantioselective protonation with R-sulfinyl alcohols 2a-e were studied. Stereoselectivity was generally enhanced when lithium bromide was present in the medium during enolization and also with the use of methylene chloride solutions. Conversely, the optimal reaction temperature varied with the R-sulfinyl alcohol used as a proton source, and its effect appears to be related to both the acidity of the proton source and the enolate structure. R-Sulfinyl alcohols 2a and 2b gave the best results when the reactions were carried out at -100°C, while the optimal temperature with 2c was -78°C. The same ee values were obtained with 2d and 2e at either -100 or -78°C. In addition, an efficient synthesis of R-sulfinyl alcohols 2b and 2c is described.

show abstract

“…Rather, the reactive constellation between BuMgCl and TMSCl intercepts the Michael adduct as a silyl ketene acetal; it is therefore in the succeeding protonation of the trapped ester enolate anion that the observed epimeric configuration is established ( Scheme 4 ). The stereoselective protonation of enolates is a concept, which has received a great deal of attention and in its purest form constitutes a biomimetic approach to establish α-chirality [ 95 , 96 , 97 , 98 ]. In our example, the pre-existing topology works in consonance to dictate which face is being protonated.…”

Section: Resultsmentioning

confidence: 99%

Stereopermutation on the Putative Structure of the Marine Natural Product Mucosin

et al. 2017

View full text Add to dashboard Cite

A stereodivergent total synthesis has been executed based on the plausibly misassigned structure of the unusual marine hydrindane mucosin (1). The topological connectivity of the four contiguous all-carbon stereocenters has been examined by selective permutation on the highlighted core. Thus, capitalizing on an unprecedented stereofacial preference of the cis-fused bicycle[4.3.0]non-3-ene system when a Michael acceptor motif is incorporated, copper-mediated conjugate addition furnished a single diastereomer. Cued by the relative relationship reported for the appendices in the natural product, the resulting anti-adduct was elaborated into a probative target structure 1*.

show abstract

A first approach to asymmetric protonation via a polymer supported chiral proton donor

Cited by 37 publications

References 6 publications

Enantioselective Protonation of the Lithium Transient Enolate of2‐Methyltetralone with 2‐Sulfinyl Alcohols

Enantioselective Protonation of the Lithium Transient Enolate of2‐Methyltetralone with 2‐Sulfinyl Alcohols

Stereoselection Parameters and Theoretical Model in the Enantioselective Protonation of Enolates with α-Sulfinyl Alcohols

Stereopermutation on the Putative Structure of the Marine Natural Product Mucosin

Contact Info

Product

Resources

About