chiral-phosphine-ligands| Page 49 of 630 | Chiral phosphine ligands

Gorbunova, Ioanna A’s team published research in Physical Chemistry Chemical Physics in 2020 | 606-68-8

Physical Chemistry Chemical Physics published new progress about Electronic transition dipole moment. 606-68-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C21H27N7Na2O14P2, Recommanded Product: ((2R,3S,4R,5R)-5-(6-Aminopurin-9-yl)-3,4-dihydroxy-oxolan-2-yl)methoxy-((((2R,3S,4R,5R)-5-(3-carbamoyl-4H-pyridin-1-yl)-3,4-dihydroxy-oxolan-2-yl)methoxy)hydroxyphosphoryl)oxyphosphinic acid disodium salt.

Gorbunova, Ioanna A.; Sasin, Maxim E.; Beltukov, Yaroslav M.; Semenov, Alexander A.; Vasyutinskii, Oleg S. published the artcile< Anisotropic relaxation in NADH excited states studied by polarization-modulation pump-probe transient spectroscopy>, Recommanded Product: ((2R,3S,4R,5R)-5-(6-Aminopurin-9-yl)-3,4-dihydroxy-oxolan-2-yl)methoxy-((((2R,3S,4R,5R)-5-(3-carbamoyl-4H-pyridin-1-yl)-3,4-dihydroxy-oxolan-2-yl)methoxy)hydroxyphosphoryl)oxyphosphinic acid disodium salt, the main research area is beta NADH disodium salt excited state dynamics anisotropic relaxation.

We present the results of exptl. and theor. studies of fast anisotropic relaxation and rotational diffusion in the first electron excited state of biol. coenzyme NADH in water-ethanol solutions The experiments have been carried out by means of a novel polarization-modulation transient method and fluorescence polarization spectroscopy. For interpretation of the exptl. results a model of the anisotropic relaxation in terms of scalar and vector properties of transition dipole moments has been developed based on the Born-Oppenheimer approximation This model allows for the description of fast isotropic and anisotropic excited state relaxation under excitation of mols. by ultrafast laser pulses in transient absorption and upconversion experiments The results obtained suggest that the dynamics of anisotropic rovibronic relaxation in NADH under excitation with 100 fs pump laser pulses can be characterised by a single vibrational relaxation time τv lying in the range of 2-15 ps and a single rotation diffusion time τr lying in the range of 100-450 ps, both depending on ethanol concentration The dependence of the times τv and τr on the solution polarity (static permittivity) and viscosity has been determined and analyzed. Limiting values of the term {P2(cos θ)} describing the rotation of the transition dipole moment in the course of vibrational relaxation have been determined from experiments as a function of ethanol concentration and analyzed.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Sagae, Hiromi’s team published research in Chemical Communications (Cambridge, United Kingdom) in 2008-08-28 | 139139-86-9

Chemical Communications (Cambridge, United Kingdom) published new progress about Alkenynes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation) (dienynes). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Name: (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.

Sagae, Hiromi; Noguchi, Keiichi; Hirano, Masao; Tanaka, Ken published the artcile< Rhodium-catalyzed enantio- and diastereoselective intramolecular [2 + 2 + 2] cycloaddition of unsymmetrical dienynes>, Name: (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is dienyne rhodium catalyst intramol cycloaddition; polycyclic cyclohexene derivative stereoselective preparation crystal structure; benzopyran derivative stereoselective preparation; biscyclooctadienerhodium tetrafluoroborate octahydrobinap asym cycloaddition catalyst.

A cationic rhodium(I)/(R)-H8-BINAP or (R)-Segphos complex catalyzes an intramol. [2 + 2 + 2] cycloaddition of unsym. dienynes, leading to fused tri- and tetracyclic cyclohexenes bearing two tertiary or quaternary carbon centers in high yields with high enantio- and diastereoselectivity.

Lipshutz, Bruce H’s team published research in Angewandte Chemie, International Edition in 2003-10-13 | 277306-29-3

Angewandte Chemie, International Edition published new progress about Aliphatic ketones Role: SPN (Synthetic Preparation), PREP (Preparation). 277306-29-3 belongs to class chiral-phosphine-ligands, and the molecular formula is C32H40FeP2, SDS of cas: 277306-29-3.

Lipshutz, Bruce H.; Servesko, Jeff M. published the artcile< CuH-catalyzed asymmetric conjugate reductions of acyclic enones>, SDS of cas: 277306-29-3, the main research area is enone conjugate copper catalyzed stereoselective reduction; alkanone asym synthesis.

A CuH-catalyzed asym. conjugate reduction of acyclic enones is reported. The reduction of enones was carried out with a catalytic amount of triphenylphosphine-copper hydride, in the presence of a chiral ligand, to afford alkanones, e.g. I, in high yields and enantiomeric excess.

Tanaka, Ken’s team published research in Organic Letters in 2005-07-07 | 139139-86-9

Organic Letters published new progress about Alkynes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Product Details of C44H40P2.

Tanaka, Ken; Nishida, Goushi; Ogino, Masakazu; Hirano, Masao; Noguchi, Keiichi published the artcile< Enantioselective synthesis of axially chiral biaryls through rhodium-catalyzed complete intermolecular cross-cyclotrimerization of internal alkynes>, Product Details of C44H40P2, the main research area is alkyne acetylenedicarboxylate cross cyclotrimerization rhodium BINAP; biaryl asym preparation; benzenetetracarboxylate preparation.

A cationic rhodium(I)/H8-BINAP complex-catalyzed complete intermol. cross-cyclotrimerization of internal alkynes with dialkyl acetylenedicarboxylates was developed. This reaction was successfully applied to enantioselective synthesis of axially chiral biaryls, e.g., I, utilizing internal alkynes bearing ortho-substituted Ph and acetoxymethyl in each terminal position. The axial chirality was constructed at the formation of benzene rings with high enantioselectivity.

Franckevicius, Vilius’s team published research in Organic Letters in 2011-08-19 | 152140-65-3

Organic Letters published new progress about Allylation catalysts, stereoselective (decarboxylative). 152140-65-3 belongs to class chiral-phosphine-ligands, and the molecular formula is C54H42N2O2P2, Computed Properties of 152140-65-3.

Franckevicius, Vilius; Cuthbertson, James D.; Pickworth, Mark; Pugh, David S.; Taylor, Richard J. K. published the artcile< Asymmetric Decarboxylative Allylation of Oxindoles>, Computed Properties of 152140-65-3, the main research area is stereoselective palladium catalyzed decarboxylative allylation oxindole allyl ester; oxindole allyl derivative stereoselective preparation; stereoselectivity reversal substituent size facial selectivity allylation.

An asym. decarboxylative palladium-catalyzed allylation of alkyl- and aryl-substituted oxindoles has been developed, enabling the installation of an all-carbon quaternary chiral center at the oxindole 3-position in excellent yields and good to excellent enantioselectivity. An intriguing substrate-dependent reversal in stereoselectivity has been observed, whereby the size of the substituent determines the facial selectivity in the allylation step.

Nogami, Juntaro’s team published research in Journal of the American Chemical Society in 2020-05-27 | 139139-93-8

Journal of the American Chemical Society published new progress about Circular dichroism (electronic). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Quality Control of 139139-93-8.

Nogami, Juntaro; Tanaka, Yusuke; Sugiyama, Haruki; Uekusa, Hidehiro; Muranaka, Atsuya; Uchiyama, Masanobu; Tanaka, Ken published the artcile< Enantioselective Synthesis of Planar Chiral Zigzag-Type Cyclophenylene Belts by Rhodium-Catalyzed Alkyne Cyclotrimerization>, Quality Control of 139139-93-8, the main research area is zigzag cyclophenylene belt enantioselective preparation; rhodium catalyst enantioselective cyclotrimerization heptynyl oxypropynylphenoxyphenylene oligomer; mol crystal structure racemic zigzag cyclophenylene belt; mechanism enantioselectivity cyclotrimerization heptynyl oxypropynylphenoxyphenylene; ring strain calculated zigzag cyclophenylene belt; fluorescence UV visible absorption zigzag cyclophenylene belt; dissymetry factor ECD CPL nonracemic zigzag cyclophenylene belt.

Planar chiral zigzag-type [8] and [12]cyclophenylene belts were prepared enantioselectively by rhodium-catalyzed enantioselective intramol. sequential cyclotrimerizations of a cyclic [oxypropynylbis(heptynyloxy)phenoxybis(heptynyl)phenylene] dimer and trimer. The observed enantioselectivity likely arose from the regioselective formation of a rhodacyclic intermediate from an unsym. triyne unit. The structure of the racemic zigzag [8]cyclophenylene belt was determined by X-ray crystallog.; the homochiral belts mesh with one another to form columns in the solid state, with columns of alternating chiralities. The ring strain of the zigzag [8]cyclophenylene belt was smaller than that of the corresponding armchair-type cycloparaphenylene despite its smaller ring size because of the presence of strain-relieving m-terphenyl moieties. The effect of the number of the benzene rings in the zigzag cyclophenylene belts on their UV/visible absorption and fluorescence was small because of the interruption of conjugation by the m-phenylene moieties, but the effect of bending on the absorption and emission peaks and on the absolute fluorescence quantum yield was significant. Modest anisotropy dissymmetry factors of the electronic CD and CPL spectra were observed for the zigzag [8]cyclophenylene belt.

Shen, Zengming’s team published research in Tetrahedron in 2006-09-25 | 139139-93-8

Tetrahedron published new progress about Amino acids Role: SPN (Synthetic Preparation), PREP (Preparation). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Related Products of 139139-93-8.

Shen, Zengming; Lu, Xiyan; Lei, Aiwen published the artcile< Highly enantioselective hydrogenation of exocyclic double bond of N-tosyloxazolidinones catalyzed by a neutral rhodium complex and its synthetic applications>, Related Products of 139139-93-8, the main research area is alkylideneoxazolidinone stereoselective hydrogenation rhodium catalyst.

A highly enantioselective synthesis of optically active N-tosyl-4-alkyl-1,3-oxazolidin-2-ones based on the asym. hydrogenation of the trisubstituted exocyclic double bond of N-tosyl-4-alkylidene-1,3-oxazolidin-2-ones under the catalysis of neutral [Rh(COD)Cl]2 and (S)-(+)-DTBM-SEGPHOS was developed. The utility of this highly enantioselective reaction was exemplified by the synthesis of optically active amino acids, amino alcs., and piperidine derivatives

Wiest, Johannes M’s team published research in Angewandte Chemie, International Edition in 2018 | 277306-29-3

Angewandte Chemie, International Edition published new progress about [2+2] Cycloaddition reaction (enantioselective, of alkenes and allenoates). 277306-29-3 belongs to class chiral-phosphine-ligands, and the molecular formula is C32H40FeP2, Application In Synthesis of 277306-29-3.

Wiest, Johannes M.; Conner, Michael L.; Brown, M. Kevin published the artcile< Synthesis of (-)-Hebelophyllene E: An Entry to Geminal Dimethyl-Cyclobutanes by [2+2] Cycloaddition of Alkenes and Allenoates>, Application In Synthesis of 277306-29-3, the main research area is hebelophyllene E sesquiterpene lactone preparation relative configuration; alkene catalytic enantioselective cycloaddition allenoate; chiral geminal dimethylcyclobutane derivatives preparation diastereoselective reduction; oxazaborolidine catalyst enantioselective cycloaddition alkene allenoate; cycloaddition; enantioselectivity; natural products; small ring systems; total synthesis.

The first synthesis of hebelophyllene E (I) is presented, along with assignment of its previously unknown relative configuration through synthesis of epi-ent-hebelophyllene E. Development of a catalytic enantioselective [2+2] cycloaddition of alkenes and allenoates provides access to the required chiral geminal dimethylcyclobutanes. Key to its success is the identification of a novel oxazaborolidine catalyst which promotes the cycloaddition in high enantioselectivities with good functional-group tolerance (9 examples, up to 97:3 e.r.). Thus, a late-stage cycloaddition using a fully functionalized alkene, followed by a diastereoselective reduction allows a concise entry to this class of natural products.

Pozo, Juan del’s team published research in Journal of the American Chemical Society in 2020-10-21 | 277306-29-3

Journal of the American Chemical Society published new progress about Alcohols, homoallylic Role: PRP (Properties), SPN (Synthetic Preparation), PREP (Preparation). 277306-29-3 belongs to class chiral-phosphine-ligands, and the molecular formula is C32H40FeP2, Quality Control of 277306-29-3.

Pozo, Juan del; Zhang, Shaochen; Romiti, Filippo; Xu, Shibo; Conger, Ryan P.; Hoveyda, Amir H. published the artcile< Streamlined Catalytic Enantioselective Synthesis of α-Substituted β,γ-Unsaturated Ketones and Either of the Corresponding Tertiary Homoallylic Alcohol Diastereomers>, Quality Control of 277306-29-3, the main research area is enantioselective synthesis substituted unsaturated ketone nitrile allene; tertiary homoallylic alc diastereomer preparation anti HIV agent transformation.

A widely applicable, practical, and scalable strategy for efficient and enantioselective synthesis of β,γ-unsaturated ketones that contain an α-stereogenic center is disclosed. Accordingly, aryl, heteroaryl, alkynyl, alkenyl, allyl, or alkyl ketones that contain an α-stereogenic carbon with an alkyl, an aryl, a benzyloxy, or a siloxy moiety can be generated from readily available starting materials and by the use of com. available chiral ligands in 52-96% yield and 93:7 to >99:1 enantiomeric ratio. To develop the new method, conditions were identified so that high enantioselectivity would be attained and the resulting α-substituted NH-ketimines, wherein there is strong C=N → B(pin) coordination, would not epimerize before conversion to the derived ketone by hydrolysis. It is demonstrated that the ketone products can be converted to an assortment of homoallylic tertiary alcs. in 70-96% yield and 92:8 to >98:2 dr-in either diastereomeric form-by reactions with alkyl-, aryl-, heteroaryl-, allyl-, vinyl-, alkynyl-, or propargyl-metal reagents. The utility of the approach is highlighted through transformations that furnish other desirable derivatives and a concise synthesis route affording more than a gram of a major fragment of anti-HIV agents rubriflordilactones A and B and a specific stereoisomeric analog.

Yang, Bo’s team published research in Angewandte Chemie, International Edition in 2020-11-23 | 139139-86-9

Angewandte Chemie, International Edition published new progress about Crystal structure. 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Reference of 139139-86-9.

Yang, Bo; Yang, Wu; Guo, Yonghong; You, Lijun; He, Chuan published the artcile< Enantioselective Silylation of Aliphatic C-H Bonds for the Synthesis of Silicon-Stereogenic Dihydrobenzosiloles>, Reference of 139139-86-9, the main research area is rhodium catalyzed enantioselective silylation cyclization styrene derivative arylsilane; silicon stereogenic dihydrobenzosilole containing dehydrocholesterol preparation crystal structure; mol structure silicon stereogenic dihydrobenzosilole containing dehydrocholesterol; C(sp3)−H silylation; asymmetric catalysis; dihydrobenzosiloles; hydrosilylation; silanes.

A Rh(I)-catalyzed enantioselective silylation of aliphatic C-H bonds for the synthesis of Si-stereogenic dihydrobenzosiloles is demonstrated. This reaction involves a highly enantioselective intramol. C(sp3)-H silylation of dihydrosilanes, followed by a stereospecific intermol. alkene hydrosilylation leading to the asym. tetrasubstituted silanes. A wide range of dihydrosilanes and alkenes displaying various functional groups are compatible with this process, giving access to a variety of highly functionalized Si-stereogenic dihydrobenzosiloles in good to excellent yields and enantioselectivities.