- High linear selectivity ligand for allyl alcohol hydroformylation
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A process for selectively producing 4-hydroxybutyraldehyde from allyl alcohol is described. The process comprises reacting allyl alcohol with a mixture of carbon monoxide and hydrogen in the presence of a solvent and a catalyst system comprising a rhodium complex and a trans-1,2-bis(bis(3,4,5-tri-n-alkylphenyl)phosphinomethyl)-cyclobutane. The process gives high yield of 4-hydroxybutyraldehyde compared to temperature.
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Page/Page column 7; 8
(2020/11/28)
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- Palladium- and Rhodium-Catalyzed Dynamic Kinetic Resolution of Racemic Internal Allenes Towards Chiral Pyrazoles
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A complementing Pd- and Rh-catalyzed dynamic kinetic resolution (DKR) of racemic allenes leading to N-allylated pyrazoles is described. Such compounds are of enormous interest in medicinal chemistry as certified drugs and potential drug candidates. The new methods feature high chemo-, regio- and enantioselectivities aside from displaying a broad substrate scope and functional group compatibility. A mechanistic rational accounting for allene racemization and trans-alkene selectivity is discussed.
- Hilpert, Lukas J.,Sieger, Simon V.,Haydl, Alexander M.,Breit, Bernhard
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p. 3378 - 3381
(2019/02/06)
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- NAPHTHENIC HYDROCARBON ADDITIVES FOR DIARYL PHOSPHIDE SALT FORMATION
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The invention relates to the use of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene and its alkyl, aryl, or heteroatom substituted analogs, that act as catalysts in the presence of an alkali metal (Li, K, Na) for the reduction of electron-deficient and electron-rich triaryl phosphines to their corresponding alkali metal diaryl phosphide salts. The process is also useful for the catalysis of triaryl phosphine chalcogen adducts such as the sulfides, oxides, and selenides, diaryl(halo)phosphines, triaryl phosphine-borane adducts, and tetra-aryl bis(phosphines) that can also be reduced to their corresponding alkali metal diaryl phosphide salts. The invention also relates to small molecule PAHs and polymer tethered PAHs naphthenics.
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Page/Page column 13
(2010/09/18)
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- Method for Producing Polyhydroxyalkanoates
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The invention relates to a process for preparing polyhydroxyalkanoates by polymerization of lactones of the general formula I, where the substituents and the index n have the meanings given in the description, in the presence of at least one catalyst of the formula (II) LIMaXam, where the substituents and indices have the meanings given in the description. The invention further relates to poly-3-hydroxybutyrates which have a novel property profile and are obtainable for the first time by means of this process, and also biodegradable polyester mixtures based on these poly-3-hydroxybutyrates.
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- Hydroformylation process
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A process for the production of 4-hydroxybutyraldehyde is described. The process comprises reacting allyl alcohol with a mixture of carbon monoxide and hydrogen in the presence of a solvent and a catalyst system comprising a rhodium complex and a 2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis[bis(3,5-di-n-alkylphenyl)phosphino]butane. The process gives high yield of 4-hydroxybutyraldehyde compared to 3-hydroxy-2-methylpropionaldehyde.
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Page/Page column 4-5
(2008/06/13)
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- Work-up-free deprotection of borane complexes of phosphines, phosphites, and phosphinites with polymer-supported amines
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Borane complexes of phosphorus compounds, a very common oxidation-free relay for catalytic ligands (phosphines, phosphites, and phosphinites), can be easily deprotected by treatment with polymer-supported piperazine or N-methylpiperazine. Deprotection conditions have been optimized for the different types of phosphorus compounds, and the resulting solutions can be used without any intermediate work-up or purification process. Georg Thieme Verlag Stuttgart.
- Sayalero, Sonia,Pericàs, Miquel A.
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p. 2585 - 2588
(2008/09/16)
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- Decarboxylative aldol reactions of allyl β-keto Esters via heterobimetallic catalysis
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Mild and selective heterobimetallic-catalyzed decarboxylative aldol reactions involving allyl β-keto esters have been developed. The reaction is promoted by Pd(0)- and Yb(III)-DIOP complexes at room temperature and involves the in situ formation of a ketone enolate from allyl β-keto esters followed by addition of the enolate to aldehydes. The reaction is a new example of heterobimetallic catalysis in which the optimized reaction conditions require the addition of both metals. Copyright
- Lou, Sha,Westbrook, John A.,Schaus, Scott E.
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p. 11440 - 11441
(2007/10/03)
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- A novel mild deprotection method for phosphine-boranes
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Treatment of phosphine-boranes with molecular sieves 4A in a mixture of an ethereal solvent and an alcohol provided deprotected free phosphines in quantitative yields. The phosphines can be obtained by a simple filtration/crystallization procedure in most cases. It should be noted that the current method is successfully applied to the deprotection of a phosphite-borane for the first time.
- Schroeder, Marc,Nozaki, Kyoko,Hiyama, Tamejiro
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p. 1931 - 1932
(2007/10/03)
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- Process for producing optically active benzhydrol compounds
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A process for producing a benzhydrol compound (II) which comprises hydrogenating a benzophenone compound (I) in the presence of a hydrogenation catalyst consisting of a transition metal complex, a base and an optically active diamine compound: STR1 wherein R1 to R10 each represents H, OH, C1-4 alkyl, C1-4 alkoxy, C1-4 alkanoyl, etc., R2 and R3, and R8 and R9 may form --CH=CH--CH=CH--, or any two of R1 to R9 adjacent to each other may be bonded to thereby form --OCH2 O-- or --(CH2)3 --. By using this process, optically active benzhydrol compounds which have a high purity and are useful as, for example, intermediates in the synthesis of drugs can be produced by simple procedures.
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- Phosphine-borane complexes; Direct use in asymmetric catalysis
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An easy and soft method of decomplexation of phosphine-borane complexes, by DABCO, allows its use in situ in asymmetric catalytic hydrogenation of double bonds with metal phosphine complexes.
- Brisset,Gourdel,Pellon,Le Corre
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p. 4523 - 4526
(2007/10/02)
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- SYNTHESE CHIRALER PHOSPHINOXIDE UND PHOSPHINE DURCH MICHAELIS-ARBUZOV-UMLAGERUNG
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Several phosphinites and phosphites, derived from chiral alcohols, were synthesized.The phosphinites were subjected to a I2-catalyzed Michaelis-Arbuzov rearrangement.Phosphinites derived from primary alcohols give satisfactory yields of the corresponding phosphineoxides.Phosphinites synthesized from secondary alcohols also undergo the rearrangement but numerous byproducts appear in the reaction mixtures.Optical resolutions of chiral phosphineoxides by crystallization with optically active acids were not successful.The corresponding phosphines can easily be prepared by reduction of the oxides with trichlorosilane.
- Brunner, H.,Zettlmeier, W.
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p. 247 - 257
(2007/10/02)
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- A NEW APPROACH TO THE SYNTHESIS OF (-)-2,3-O-ISOPROPYLIDENE-2,3-DIHYDROXY-1,4-BIS(DIPHENYLPHOSPHINO)BUTANE(DIOP)
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(-)-2,3-O-Isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane (DIOP) has been prepared by reaction of (-)-1,2:3,4-diepoxybutane with lithium diphenylphosphide followed by ketalisation with 2,2-dimethoxypropane.
- Zhang, San-qi,Zhang, Sheng-yong,Feng, Rui
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p. 173 - 174
(2007/10/02)
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- Einfluesse von in para-Position zum Phosphor eingefuehrten Substituenten in das Diop-System auf die optische Induktion bei der asymmetrischen Hydrierung von Acylaminoacrylsaeureethylester und (Z)-Acylamino-zimtsaeuremethylester mit kationischen Rhodium-(Diop-Derivat)-Komplexen. I
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(R,R)-Diop was modified at the diphenylphosphino group by the introduction of substituents in para-position to the phosphorus atoms.The influence of the substituents on the optical induction was examined for the hydrogenation of ethyl α-acylaminoacrylate (AAEE) and (Z)-methyl α-acylaminocinnamate (AZME) with + BF4- as catalyst.For both substrates the substituents affected the optical induction markedly.The observed effects can be attributed to the electronical features, solvation and in special cases also to the size of the substituents.
- Werz, Udo,Brune, Hans-Albert
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p. 377 - 386
(2007/10/02)
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- Novel Copper Complexes of Chiral Diphosphines: Preparation, Structure, and Use To Form Rhodium Complex Catalysts for Chiral Hydrogenations
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Treatment of chiral diphosphines 5a-c and 13 ("DIOP", aryl derivatives and related substances) with CuCl in boiling ethanol gave complexes having the composition n, 6a-c and 11.Crystallizations of 6a-c from crude 70-80percent pure 5a-c and decomposition of the complexes by ammonia gave the pure diphosphines.Ligand exchange between 6a-c and 2 in methanol at 23 deg C was rapid and complete.Treatment of the resulting solutions with H2 gave active catalysts for asymmetric hydrogenations.
- Townsend, John M.,Blount, John F.,Sun, Ruen Chu,Zawoiski, Sonja,Valentine, Donald
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p. 2995 - 2999
(2007/10/02)
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