33496-83-2

Upstream product

• 78-59-1 3,5,5-Trimethylcyclohex-2-en-1-one 
• 873-94-9 dihydroisophorone 
• 147-85-3 L-proline 
• 67217-68-9 1,1-dimethoxy-3,3,5-trimethyl-cyclohexane 

Relevant academic research and scientific papers

Heterogeneously catalyzed asymmetric C=C hydrogenation: Origin of enantioselectivity in the proline-directed Pd/isophorone system

We have studied the proline-directed, Pd-catalyzed enantioselective hydrogenation of isophorone in the liquid state using a variety of methods. Our results unambiguously reveal the true reaction pathway and demonstrate that all earlier mechanistic hypothe

New P-chirogenic tert.-butyl-xantphos ligands and their application in asymmetric hydrogenation and alkylation

The synthesis of a broad library of new P-chirogenic Xantphos ligands is reported. A special feature is 2,7-di-tert.-butyl substituents in the backbone which requires the modification of the original synthetic approach. In comparison to related ligands reported formerly the substitution has a considerable influence on the results (yield and % e.e.) of metal catalyzed reactions, e.g. asymmetric rhodium catalyzed hydrogenation of isophorone and the palladium catalyzed alkylation, respectively.

P-CHIRAL PHOSPHINE LIGANDS AND USE THEREOF FOR ASYMMETRIC SYNTHESIS

The present invention relates to chiral compounds with two optically active phosphorus atoms, chiral transition metal catalysts which comprise these compounds as ligands, a process for preparing the P-chiral compounds and processes for asymmetric synthesis using the chiral transition metal catalysts. The present invention specifically relates to a process for preparing an optically active carbonyl compound by asymmetric hydrogenation of a prochiral α,β-unsaturated carbonyl compound with hydrogen in the presence of an optically active transition metal catalyst according to the invention. Yet more specifically, the present invention relates to a process for the asymmetric hydrogenation of citral, and also a process for preparing optically active menthol.

Method for preparing chiral 3,3,5-trimethylcyclohexanone

The invention relates to a method for preparing chiral 3,3,5-trimethylcyclohexanone. The method comprises the steps of directly adding IP, a PEG stabilized nano Pd catalyst, a roasted Al2O3 carrier and S-proline into a solvent, and carrying out a reaction

P-Chirogenic Xantphos Ligands and Related Ether Diphosphines: Synthesis and Application in Rhodium-Catalyzed Asymmetric Hydrogenation

A series of P-chirogenic Xantphos ligands and related diaryl ether diphosphines have been synthesized by a modification of the well-established Jugé method. The approach consists of the in situ deboranation of the chiral ephedrine-based phosphinite before the P-C coupling takes place. The stereochemical integrity of the stereocenters of the diphosphines during synthesis, long-time storage, and catalytic application was evaluated. In the rhodium-catalyzed asymmetric hydrogenation of isophorone as a model substrate for industrially relevant prostereogenic enones with some of the diphosphines, almost complete conversion, high chemoselectivity, and 96% ee were achieved.

Two "classical" Old Yellow Enzymes from Chryseobacterium sp. CA49: Broad substrate specificity of Chr-OYE1 and limited activity of Chr-OYE2

Two putative Old Yellow Enzyme (OYE) homologues, Chr-OYE1 and Chr-OYE2, were identified from the genome of Chryseobacterium sp. CA49 as new members of the "classical" subfamily. Chr-OYE1 and Chr-OYE2 were most closely related to the SYE4 from Shewanella oneidensis and NerA from Agrobacterium radiobacter with 41% and 45% identity, respectively. Both enzymes were expressed in Escherichia coli in soluble form, but their catalytic abilities as ene-reductases were quite different. Among the 19 substrate tested, Chr-OYE1 could catalyze the reduction of 18 of them including an ynone with excellent stereoselectivity for several prochiral ones, and its specific activity was roughly 1100-fold high than Chr-OYE2, which only catalyzed 3 of the substrates. After restoring the conserved tyrosine, Chr-OYE2 remained the same substrate spectrum, but showed significantly enhanced activity and stereoselectivity.

New biobased tetrabutylphosphonium ionic liquids: Synthesis, characterization and use as a solvent or co-solvent for mild and greener Pd-catalyzed hydrogenation processes

Phosphonium-based Ionic Liquids (PhosILs) with natural organic derived anions (l-lactate, l-tartrate, malonate, succinate, l-malate, pyruvate, d-glucuronate, d-galacturonate, ferulate, p-coumarate) were easily prepared by acid-base method from tetrabutylphosphonium hydroxide and an excess of the corresponding acid with good yields. Their characterization was realized through classical NMR, IR and elemental analysis techniques; their viscosity and ATG parameters were also determined. These ionic liquids showed good performance and recyclability in the selective Pd-catalyzed hydrogenation of alkenes, polyenes like linoleic acid and enantioselective hydrogenation of unsaturated ketones such as isophorone at room temperature under atmospheric H2 pressure. Furthermore, NMR studies leading to computational calculations were performed to establish easily the composition of the resulting mixture obtained through the hydrogenation of linoleic acid.

Enantioselection on Heterogeneous Noble Metal Catalyst: Proline-Induced Asymmetry in the Hydrogenation of Isophorone on Pd Catalyst

In the (S)-proline-mediated asymmetric hydrogenation of isophorone (IP) on supported Pd catalyst, excellent enantioselectivity is achieved, with an enantiomeric excess of up to 99%. The role of the heterogeneous catalyst has been the subject of a controve

Identification, characterization, and application of three enoate reductases from Pseudomonas putida in in vitro enzyme cascade reactions

Enoate reductases are versatile enzymes for the enantio- and regioselective addition of hydrogen to double bonds. We identified three EREDs (XenA, XenB, NemA) from Pseudomonas putida ATCC 17453 through a sequence motif search. In addition to cloning, functional expression, and biochemical characterization of these enzymes, the enoate reductases were also applied in enzyme cascade reactions in combination with a Baeyer-Villiger monooxygenase and an alcohol dehydrogenase to produce lactones. Good things come in threes: The identification, cloning, expression, and characterization of three enoate reductases from Pseudomonas putida reveal broad substrate scope and high stereoselectivities. Furthermore, the enoate reductases could be integrated into cascade reactions together with an alcohol dehydrogenase and a Baeyer-Villiger monooxygenase.

Tetrabutylammonium prolinate-based ionic liquids: A combined asymmetric catalysis, antimicrobial toxicity and biodegradation assessment

Chiral ionic liquids (CILs) tetrabutylammonium-(S)-prolinate, tetrabutylammonium-(R)-prolinate and tetrabutylammonium trans-4-hydroxy-(S)- prolinate were investigated as chiral additives in the Pd-catalyzed enantioselective hydrogenation of α,β-unsaturated ketones. These CILs were easily prepared in one step from the aminoacid and tetrabutylammonium hydroxide and characterized (NMR, IR, optical rotation, elemental analysis, DSC, viscosity, decomposition temperature). The research strategy was to assess the antimicrobial toxicity (>20 strains) and biodegradability (OECD 301D) of the CILs at the same time as undertaking the asymmetric catalysis study. The Pd-catalyzed enantioselective hydrogenation of the carbon-carbon double bond of α,β-unsaturated ketones under mild conditions (room temperature, 1 atm of H2) in different solvents with CILs present. The best results were obtained in i-PrOH after 18 hours of reaction with a i-PrOH/IL ratio of 5. While all three CILs have low antimicrobial toxicity to a wide range of bacteria and fungi, tetrabutylammonium-(S)-prolinate, tetrabutylammonium-(R)-prolinate and tetrabutylammonium trans-4-hydroxy-(S)-prolinate did not pass the Closed Bottle biodegradation test.