Asymmetric Hydroformylation Of Vinyl Acetate Research Articles

Highly Efficient Rhodium Catalysts for the Asymmetric Hydroformylation of Vinyl and Allyl Ethers using C1‐Symmetrical Diphosphite Ligands

AbstractHere, we describe the successful application of novel glucofuranose‐derived 1,3‐diphosphites in the rhodium‐catalysed asymmetric hydroformylation of vinyl acetate, 2,5‐dihydrofuran and 2,3‐dihydrofuran. In the hydroformylation of vinyl acetate, total regioselectivity and high ee (up to 73%) were obtained. When 2,3‐ and 2,5‐dihydrofuran were the substrates, total chemo‐ and regioselectivities were achieved together with ees up to 88%. These results correspond to the highest ee values reported to date in the asymmetric hydroformylation of these substrates. The HP‐NMR studies of the [RhH(CO)2(L)] species (L=15 and 17) demonstrated that both ligands coordinate to the Rh centre in an eq‐eq fashion. The complex [RhH(CO)2(15)] was detected as a single isomer with characteristic features of eq‐eq coordination. However, the broadening of the corresponding signals indicated that this species is rapidly interchanging in solution. In contrast, complex [RhH(CO)2(17)] was detected as a mixture of two conformational isomers at low temperature due to the greater flexibility of the monocyclic backbone of this ligand.

Ferrocene-based bidentate phosphonite ligands for rhodium(I)-catalyzed enantioselective hydroformylation

A new class of chiral modular bidentate phosphonite ligands has been synthesized in good overall yields by using cheap trans-1,2-diaminocyclohexane and ferrocene as starting materials, and applied in the Rh(I)-catalyzed asymmetric hydroformylation of vinyl acetate and styrene to afford the corresponding optically active aldehydes with good regioselectivity (up to 16.9 b/ l ratio) and moderate to good enantioselectivity (up to 83% ee). The substituents on the backbone of the ligands are found to exhibit a remarkable effect on both the regio- and enantioselectivity of the catalysis.

Asymmetric Hydroformylation of Vinyl Acetate: Application in the Synthesis of Optically Active Isoxazolines and Imidazoles

(R)- and (S)-2-(Acetyloxy)-propanal were prepared [93.8% ee, 102 b/l for (R), 96.9% ee, 149 b/l for (S)] via asymmetric hydroformylation of vinyl acetate on a 150-180 g scale and were used as the starting materials in the synthesis of chiral isoxazoline and imidazole derivatives which proceeded without racemization of the chiral center.

New diphosphite ligands for enantioselective asymmetric hydroformylation

A series of new diphosphite ligands have been easily prepared from BINOL derivatives; moderate enantioselectivities (up to 80% ee) and excellent regioselectivities (b/l up to 98/2) have been achieved in the Rh-catalyzed asymmetric hydroformylation of vinyl acetate.

Biphasic asymmetric hydroformylation and hydrogenation by water-soluble rhodium and ruthenium complexes of sulfonated ( R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl in ionic liquids

A biphasic catalytic system with water-soluble rhodium complexes of sulfonated ( R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (labeled as ( R)-BINAPS) in ionic liquid BMI·BF 4 has been developed for the asymmetric hydroformylation of vinyl acetate under mild conditions. The corresponding ruthenium complexes have been investigated for the biphasic asymmetric hydrogenation of dimethyl itaconate. The biphasic asymmetric hydroformylation of vinyl acetate provided 28.2% conversion and 55.2% enantiomeric excess when BMI·BF 4–toluene was used as the reaction medium at 333 K and 1.0 MPa for 24 h. The biphasic asymmetric hydrogenation of dimethyl itaconate in BMI·BF 4– i PrOH at 333 K and 2.0 MPa afforded 65% enantiomeric excess with an activity similar to the homogenous analogs. Both biphasic catalytic systems with ( R)-BINAPS ligand could be reused several times without significantly decrease in the activity, enantio- and regio-selectivities. The effects of properties of ionic liquid, molar ratio of ligand to rhodium, temperature, pressure and reaction time have been discussed.

Synthesis and applications of chiral phosphite ligands derived from incompletely condensed silsesquioxane backbones

The synthesis of novel chiral tri- and bidentate phosphites 2, 5, 6 and 8, derived from incompletely condensed silsesquioxane backbones and binaphthol, is described. These compounds can be obtained in good yield and are characterized by multinuclear NMR spectroscopy, mass spectrometry and elemental analyses. The complexation with [Rh(cod) 2]BF 4 has been studied for all bidentate ligands. These nanosized ligands have been applied in the rhodium-catalyzed asymmetric hydroformylation of vinyl acetate and in the rhodium-catalyzed hydrogenation of methyl-( Z)-2-acetamidocinnamate.

Parallel ligand screening on olefin mixtures in asymmetric hydroformylation reactions.

[reaction: see text] Herein we describe a new protocol for catalyst evaluation in asymmetric hydroformylation reactions where multisubstrate screening is performed in an array of parallel reactors. This method was successfully demonstrated using a mixture of styrene, allyl cyanide, and vinyl acetate. Using this screening methodology, a set of phosphite ligands was evaluated and led to the discovery of a bisphosphite ligand that gave 88% ee and unprecedented >100:1 branched:linear regioselectivity in asymmetric hydroformylation of vinyl acetate.

Aminophosphonite-phosphite and aminophosphonite-phosphinite ligands with mixed chirality: preparation and catalytic applications in asymmetric hydrogenation and hydroformylation

Aminophosphonite-phosphite and aminophosphonite-phosphinite chiral ligands with mixed stereogenic elements have been prepared in good yields from chiral α-aminoalcohols such as 2-(hydroxymethyl)pyrrolidine and 2-N-ethylammino-1-butanol. These new ligands have been fully characterized; the Rh(I) complexes have been tested in catalytic hydrogenation and hydroformylation reactions. Enantioselectivities up to 70% have been obtained in asymmetric hydrogenation of α-acetamidocinnamic acid, methyl ester; enantioselectivities higher than 30% and regioselectivities higher than 98% have been obtained in asymmetric hydroformylation of vinyl acetate.

Asymmetric hydroformylation of vinyl acetate catalyzed by zeolite‐supported gelatin–Co–Ru complex

AbstractZeolite‐supported gelatin–cobalt–ruthenium complex (zeo–gelatin–Co–Ru) was prepared by a simple method, first the zeolite and gelatin (chiral natural bio‐polymer) were mixed to give zeolite‐supported gelatin (zeo–gelatin), then this was used as a polymer ligand to react with CoCl2·6H2O and RuCl3·H2O to form the complex. This complex has been found to catalyze the asymmetric hydroformylation of vinyl acetate to give (R)‐2‐acetoxy‐propanal in 83.4% product yield and 90.9% optical yield. And this catalyst could be reused several times without any considerable change in the optical yield. Copyright © 2001 John Wiley & Sons, Ltd.

Rhodium-Mediated Asymmetric Hydroformylation with a Novel Bis(diazaphospholidine) Ligand We thank the EPSRC for generous funding of this project, and Prof. D. Games and Dr. B. Stein of the EPSRC Mass Spectrometry Service at Swansea for carrying out analyses of certain compounds. We are also very grateful to the Scottish Higher Education Funding Council for funding the Catalyst Evaluation and Optimisation

A gas pressure of only 8 bar is required for the effective asymmetric hydroformylation of vinyl acetate with a new class of rhodium(I) catalysts. Key to successful catalysis is the chiral bis(diazaphospholidine) ligand ESPHOS. With 0.250 mol % of this catalyst, hydroformylation of vinyl acetate was achieved in 90 % yield, a branched:linear ratio of 17.3:1, and 89 % ee (see scheme).

Asymmetric Hydroformylation of Olefins in Highly Crosslinked Polymer Matrixes

Abstract When polymer-immobilized chiral phosphine-phosphite–Rh(I) complexes were used, the asymmetric hydroformylation of styrene gave 2- and 3-phenylpropanals with a substrate/catalyst ratio of 2000, iso/normal ratios of 84/16 to 89/11, and 89% R enantiomeric excess of 2-phenylpropanal; these results were at the highest level in catalytic activity, regio-, and enantioselectivities. Recovery-reuse of the catalyst was examined. Asymmetric hydroformylation of vinyl acetate, (Z)-2-butene, and 3,3,3-trifluoropropene was also successfully performed with the polymer-supported catalysts.

Asymmetric hydroformylation of vinyl acetate with BINAP–rhodium(I) complexes

Complexes of ( R)-BINAP (BINAP=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) derived from the available rhodium precursors Rh(acac)(CO) 2 and [Rh(μ-OMe)(cod)] 2 are used for the asymmetric hydroformylation of vinyl acetate. Enantiomeric excesses of up to 60% are achieved with regioselectivities of up to 99%. Only a BINAP/Rh ratio of 2 is required. Effects of pressure and temperature on catalyst stability, enantio- and chemoselectivity are discussed.

Construction of chiral Ti(IV)–Rh(I)–salenophos complexes and their application in the asymmetric hydroformylation of functionalised olefins

The synthesis of new chiral salenophos-type ligands bearing `hard' and `soft' coordination sites is described. The polyfunctionalised ligands are used for the construction of monometallic and early–late heterobimetallic complexes. In the reaction with titanium(IV) reagents the salen subunit selectively coordinated to the `hard' metal. The phosphine groups in turn can be coordinated to rhodium(I). The coordination geometry of the diphosphine–Rh subunit is strongly influenced by the counter ligands COD or CO and Cl, respectively. In the asymmetric hydroformylation of vinyl acetate with one of the Rh–Ti-complexes, the branched aldehyde is predominantly formed with 30% ee.

New carbohydrate bisphosphites as chiral ligands

The synthesis of the 2,3-bisphosphite derivatives of phenyl 4,6- O-benzylidene-β-D-glucopyranoside leads to new chelating ligands. Their rhodium(I) and platinum(II) complexes have been tested as catalysts for the asymmetric hydroformylation of vinyl acetate, allyl acetate and p-methoxystyrene. Good regioselectivity (>90% branched product), but an enantioselectivity of only ≤36% ee were found under mild reaction conditions (25–40°C, 40–70 bar syngas).

Asymmetric hydroformylation of vinyl acetate by use of chiral bis(triarylphosphite)-rhodium(I) complexes

Bis(triarylphosphite) ligands 1–4 were prepared in optically pure forms from (R)- or (S)-binaphthol and (ArO) 2PCl, and their Rh(I) complexes have been used as catalysis for hydroformylation of vinyl acetate. The corresponding branched aldehyde, 2-acetoxypropanal, was given in up to 95% regioselectivity and in 49% ee.

Asymmetric hydroformylation of vinyl acetate with DIOP-type ligands

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAsymmetric hydroformylation of vinyl acetate with DIOP-type ligandsCharles F. Hobbs and W. S. KnowlesCite this: J. Org. Chem. 1981, 46, 22, 4422–4427Publication Date (Print):October 1, 1981Publication History Published online1 May 2002Published inissue 1 October 1981https://doi.org/10.1021/jo00335a020RIGHTS & PERMISSIONSArticle Views820Altmetric-Citations72LEARN 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 (757 KB) Get e-Alerts Get e-Alerts

The Asymmetric Hydroformylation of Vinyl Acetate

Abstract Vinyl acetate gives selectively (S)-2-acetoxypropanal in 10–24% optical yields by the asymmetric hydroformylation with μ,μ′-dichlorotetracarbonyldirhodium–(−)-DIOP. (R)-Benzylmethylphenylphosphine and neomenthyldiphenylphosphine give low optical yields. The reaction depends essentially on the DIOP/rhodium ratio. Just 2 mol or more of (−)-DIOP per g-atm of rhodium is required for the asymmetric reaction. Other reaction variables (temperatures and pressures of hydrogen and carbon monoxide) have minor effects.