Chiral Phase-transfer Catalysts Research Articles

ChemInform Abstract: Efficient Catalytic Asymmetric Alkylations. Part 2. Enantioselective Robinson Annulation Under Phase Transfer Catalysis.

AbstractThe derivatives (I) and (II) of cinchonine and cinchonidine, resp., are employed as chiral phase transfer catalysts in the alkylation of (IV) with the methyl vinyl ketone equivalent (III).

Enantioselective Robinson Annelations via Phase‐Transfer Catalysis

Alkaloids as chiral phase transfer catalysts effect enantioselective alkylation of 1, R = Pr, with the methyl vinyl ketone synthetic equivalent 1,3-dichloro-2-butene to give 2, R1 = Pr, R2 = CH2CH = C(Cl)CH3. The two enantiomers are obtained with 92 and 78% ee, respectively, and, in each case, in 99% yield; cinchoninium and cinchonidinium derivatives serve as catalysts. The results are explained in terms of an intermediate formation of a tight ion pair.

Some novel polymer-supported optically active phase transfer catalysts: 2. Use in displacement, reduction, epoxidation and addition reactions

The performance of 27 novel polymer-supported chiral phase transfer catalysts in a range of phase separated reactions has been studied. The later include a number of displacement reactions, sodium borohydride reductions of prochiral ketones, the epoxidation of chalcone, the addition of nitromethane to chalcone and the addition of thiophenol to cyclohexenone. Some of the reactions were performed under liquid/liquid conditions and others using solid/liquid. No systematic difference emerged between these. In general many of the catalysts provided fast reactions and good chemical yields of products. However, in no case was any significant enantiomeric excess achieved. The latter observation is discussed in the light of the reported behaviour of analogous non-supported catalytic systems, and suggestions proposed to explain these differences.

Induced circular dichroism in the 2-benzoylbenzoate anion paired with polymer-supported optically active quaternary ammonium ions

Induced circular dichroism in the 2-benzoylbenzoate Anion paired with optically active ammonium ions provides a potentially useful and highly convenient probe for assessing chiral phase transfer catalysts.

Synthesis of New Chiral Phase-transfer Catalysts and Their Application to Michael Additions

Abstract A series of chiral onium salts derived from (l)-(+)-methionine have been examined for the catalysis of Michael additions in phase-transfer conditions. The chemical yields are high, but no asymmetric induction was observed. Catalyst 6 represents the first example of an onium salt anchored to a polimeric matrix having a higher catalytic efficiency than its soluble counterpart.

Asymmetric induction in the Michael reaction by means of chiral phase-transfer catalysts derived from cinchona and ephedra alkaloids

Download options Please wait... Article information DOI https://doi.org/10.1039/P19810000547 Article type Paper Download Citation J. Chem. Soc., Perkin Trans. 1, 1981, 547-552 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Asymmetric induction in the Michael reaction by means of chiral phase-transfer catalysts derived from cinchona and ephedra alkaloids S. Colonna, A. Re and H. Wynberg, J. Chem. Soc., Perkin Trans. 1, 1981, 547 DOI: 10.1039/P19810000547 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Stefano Colonna Alberto Re Hans Wynberg

Azapropellanes as phase-transfer catalysts. I. Introduction and synthesis of (±)1-azoniatricyclo[4.4.4.01,6]tetradecane and(±)1-azoniatricyclo[4.4.3.01,6]tridecane salts

The rationale for considering 1-azoniapropellane salts as potential chiral phase-transfer catalysts is presented. The synthesis of two examples of these types of molecules is outlined and their efficacy in phase-transfer catalyzed reactions is established.

Michael additions to α,β-unsaturated sulphoximides in two-phase systems. Kinetic resolution by means of chiral phase-transfer catalysts

Addition of nucleophiles to α,β-unsaturated sulphoximides is a facile reaction in two-phase systems. The chiral phase-transfer catalyst N-benzylquininium chloride is capable of asymmetric selection in the reaction of the α,β-unsaturated sulphoximides with thiols, enantiomeric excesses being in the range 1–13%.

Oxidation of Olefins with Potassium Permanganate in the Presence of Chiral Phase Transfer Catalysts

Oxidation of Olefins with Potassium Permanganate in the Presence of Chiral Phase Transfer Catalysts

Enantioselective Alkylation Using Optically Active Phase Transfer Catalyst

Abstract Synthesis of optically active benzyl[cis-2-(hydroxymethyl)cyclohexyl]dimethylammonium bromide (3) and its application to asymmetric synthesis were studied. It was found that 3 was as effective as (−)-N-benzyl-N-methylephedrinium bromide in the enantioselective alkylation of active methylene compounds when it was employed as a chiral phase transfer catalyst.

Cis, TransStereochemistry and Asymmetric Induction in the Synthesis of Epoxides from Aryl Aldehydes and Phenacyl Halides in a Two-Phase System in the Presence of Chiral Phase-Transfer Catalysts

Abstract Reactions under phase-transfer conditions in the presence of chiral catalysts constitute an actractive route to optically active epoxides.

ChemInform Abstract: PHASE‐TRANSFER CATALYSIS USING CHIRAL CATALYSTS. SYNTHESIS OF OPTICALLY ACTIVE 2‐PHTHALIMIDO‐ESTERS

AbstractUnter Phasentransferbedingungen liefert der Bromcarbonsäureester (II) mit Phthalimidkalium in Gegenwart von (‐)‐1‐Benzylcinchonidiniumchlorid bzw. (+)‐1‐Benzyl‐cinchoniniumchlorid den (S)‐ bzw. (R)‐Ester (III) in 12,1 bzw. 19,l%iger optischer Reinheit.

Asymmetric reduction of .ALPHA.-ketoesters with sodium borohydride by chiral phase transfer catalysts.

Single and double asymmetric inductions were achieved by the sodium borohydride reduction of α-ketoesters in the presence of chirai phase transfer catalysts. The quaternary ammonium salts with hydroxyl group in the substituent moiety showed the effective catalytic activity. The reduction of (–)-(3R)-menthyl benzoylformate gave (3R)-menthyl (S)-mandelate in contrast to the prediction by the Prelog rule.

Phase-transfer catalysis using chiral catalysts. Synthesis of optically active 2-phthalimido-esters

Reaction between (±)-2-bromoalkanoates and potassium phthalimide, under solid–liquid phase-transfer conditions, using either (–)-1-benzylcinchonidium chloride or (+)-1-benzylcinchoninium chloride as chiral phase-transfer catalysts, gives optically active 2-phthalimido-esters.

Asymmetric induction in the borohydride reduction of carbonyl compounds by means of chiral phase-transfer catalysts. Part 2

Reaction of carbonyl compounds with sodium borohydride in a two-phase system, in the presence of chiral ammonium salts containing a secondary hydroxy-group affords the corresponding carbinols with 0–32% enantiomeric excess. The optical yields are higher when the hydroxy group is β to the ‘onium’ function and the catalyst is conformationally more rigid.

Additions and Corrections - Enantioselective Oxirane Synthesis by Means of Dimethylsulfonium Metylide and Chiral Phase-Transfer Catalysts

Additions and Corrections - Enantioselective Oxirane Synthesis by Means of Dimethylsulfonium Metylide and Chiral Phase-Transfer Catalysts

Asymmetric Induction in the Borohydride Reduction of Carbonyl Compounds by Means of a Chiral Phase-Transfer Catalyst

Asymmetric Induction in the Borohydride Reduction of Carbonyl Compounds by Means of a Chiral Phase-Transfer Catalyst

Enantioselective oxirane synthesis by means of dimethylsulfonium methylide and chiral phase-transfer catalysts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnantioselective oxirane synthesis by means of dimethylsulfonium methylide and chiral phase-transfer catalystsTamejiro Hiyama, Takashi Mishima, Hiroyuki Sawada, and Hitosi NozakiCite this: J. Am. Chem. Soc. 1975, 97, 6, 1626–1627Publication Date (Print):March 1, 1975Publication History Published online1 May 2002Published inissue 1 March 1975https://doi.org/10.1021/ja00839a086RIGHTS & PERMISSIONSArticle Views292Altmetric-Citations50LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (298 KB) Get e-Alerts Get e-Alerts

Asymmetric alkylation reaction by means of a chiral phase transfer catalyst.

Asymmetric alkylation reaction by means of a chiral phase transfer catalyst.