Deracemization of silyl enol ethers

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

doi:10.1016/s0957-4166(00)82229-6

Cited by 23 publications

(7 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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

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

show abstract

“…The recent use of a chiral proton donor attached to polystyrene achieves this and perhaps equally important offers a methodology far superior to the nonsupported analogue [93]. In this work (D)-mandelic acid has been bound to chloromethylated polystyrene via its carboxylic acid.…”

Section: Asymmetric Catalystsmentioning

confidence: 99%

Polymer-supported synthesis

Sherrington¹

1995

Chemistry of Waste Minimization

View full text Add to dashboard Cite

“…Most of these reactions proceed via enolate anion/enols under basic or neutral conditions. The acid‐promoted hydrolysis of enol ethers is an interesting alternative; however, the enantioselectivity in this case has received little attention 32–36. Silyl enol ethers, which are synthetic equivalents of enols or enolates, are more stable than the corresponding metal enolates and can be isolated.…”

Section: Introductionmentioning

confidence: 99%

“…Silyl enol ethers, which are synthetic equivalents of enols or enolates, are more stable than the corresponding metal enolates and can be isolated. If the protonolysis of silyl enol ethers favors C ‐protonation or initial O ‐protonation, with subsequent transfer of the proton under influence of the ligand, it should be possible to develop an enantioselective protonation of achiral silyl enol ethers with the use of chiral proton donors (Scheme ) 32,33…”

Section: Introductionmentioning

confidence: 99%

Chiral Proton Donor Reagents: Tin Tetrachloride—Coordinated Optically Active Binaphthol Derivatives

Ishibashi

Ishihara

Yamamoto

2002

The Chemical Record

View full text Add to dashboard Cite

The Lewis acid-assisted chiral Brønsted acids (chiral LBAs), which are prepared from tin tetrachloride and optically active binaphthol derivatives, are highly effective chiral proton donor reagents for enantioselective protonation and biomimetic polyene cyclization. These chiral LBAs can directly protonate various silyl enol ethers and ketene disilyl acetals to give the corresponding alpha-aryl or alpha-halo ketones and alpha-arylcarboxylic acids, respectively, with high enantiomeric excess (up to 98% ee). A catalytic version of enantioselective protonation was also achieved using stoichiometric amounts of 2,6-dimethylphenol and catalytic amounts of monomethyl ether of optically active binaphthol in the presence of tin tetrachloride. The biomimetic cyclization of simple isoprenoids to polycyclic isoprenoids using chiral LBA is also described. This is the first example of a chiral Brønsted acid-induced enantioselective ene cyclization in synthetic chemistry. Geranyl phenyl ethers, o-geranylphenols, and homogeranylphenol derivatives were directly cyclized in the presence of (R)-binaphthol derivatives and tin tetrachloride (up to 90% ee). Compounds bearing a farnesyl group could also be cyclized under the same conditions to give the natural products (-)-ambrox((R)) and (-)-chromazonarol, and (-)-tetracyclic polyprenoids of sedimentary origin. These chiral LBAs recognize the prochiral face of a trisubstituted terminal olefin and site selectively generate carbocations on the substrates.

show abstract

Deracemization of silyl enol ethers

Cited by 23 publications

References 19 publications

Stereopermutation on the Putative Structure of the Marine Natural Product Mucosin

Stereopermutation on the Putative Structure of the Marine Natural Product Mucosin

Polymer-supported synthesis

Chiral Proton Donor Reagents: Tin Tetrachloride—Coordinated Optically Active Binaphthol Derivatives

Contact Info

Product

Resources

About