Category: chiral-phosphine-ligands

Duan, Ying; Li, Lu; Chen, Mu-Wang; Yu, Chang-Bin; Fan, Hong-Jun; Zhou, Yong-Gui published the artcile< Homogeneous Pd-Catalyzed Asymmetric Hydrogenation of Unprotected Indoles: Scope and Mechanistic Studies>, Electric Literature of 139139-86-9, the main research area is homogeneous palladium catalyzed asym hydrogenation unprotected indole.

An efficient palladium-catalyzed asym. hydrogenation of a variety of unprotected indoles has been developed that gives up to 98% ee using a strong Bronsted acid as the activator. This methodol. was applied in the facile synthesis of biol. active products containing a chiral indoline skeleton. The mechanism of Pd-catalyzed asym. hydrogenation was investigated as well. Isotope-labeling reactions and ESI-HRMS proved that an iminium salt formed by protonation of the C=C bond of indoles was the significant intermediate in this reaction. The important proposed active catalytic Pd-H species was observed with 1H NMR spectroscopy. It was found that proton exchange between the Pd-H active species and solvent trifluoroethanol (TFE) did not occur, although this proton exchange had been previously observed between metal hydrides and alc. solvents. D. functional theory calculations were also carried out to give further insight into the mechanism of Pd-catalyzed asym. hydrogenation of indoles. This combination of exptl. and theor. studies suggests that Pd-catalyzed hydrogenation goes through a stepwise outer-sphere and ionic hydrogenation mechanism. The activation of hydrogen gas is a heterolytic process assisted by trifluoroacetate of Pd complex via a six-membered-ring transition state. The reaction proceeds well in polar solvent TFE owing to its ability to stabilize the ionic intermediates in the Pd-H generation step. The strong Bronsted acid activator can remarkably decrease the energy barrier for both Pd-H generation and hydrogenation. The high enantioselectivity arises from a hydrogen-bonding interaction between N-H of the iminium salt and oxygen of the coordinated trifluoroacetate in the eight-membered-ring transition state for hydride transfer, while the active chiral Pd complex is a typical bifunctional catalyst, effecting both the hydrogenation and hydrogen-bonding interaction between the iminium salt and the coordinated trifluoroacetate of Pd complex. Notably, the Pd-catalyzed asym. hydrogenation is relatively tolerant to oxygen, acid, and water.

Journal of the American Chemical Society published new progress about Acid catalysis (strong Bronsted acids as activators). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Electric Literature of 139139-86-9.

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

Tanaka, Ken; Otake, Yousuke; Sagac, Hiromi; Noguchi, Keiichi; Hirano, Masao published the artcile< Highly regio-, diastereo-, and enantioselective [2 + 2 + 2] cycloaddition of 1,6-enynes with electron-deficient ketones catalyzed by a cationic RhI/H8-binap complex>, Computed Properties of 139139-86-9, the main research area is enyne stereoselective cyclocondensation keto ester amide diketone; rhodium BINAP regioselective diastereoselective enantioselective cycloaddition ortho functionalization; pyran dihydro heterocycle fused regioselective stereoselective preparation; ketone aryl ortho functionalization enyne rhodium catalyst.

A cationic RhI/H8-binap complex catalyzed regio-, diastereo-, and enantioselective [2 + 2 + 2] cycloaddition of 1,6-enynes with electron-deficient ketones to form fused dihydropyrans containing two quaternary carbon centers, e.g., I, is reported. Electron-rich aryl ketones react with 1,6-enynes in the presence of the same catalyst to give ortho-functionalized aryl ketones with excellent regio- and enantioselectivity.

Angewandte Chemie, International Edition published new progress about Alkenynes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation) (1,6-). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Computed Properties of 139139-86-9.

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

Palka, Katarzyna; Kanska, Marianna published the artcile< Enzymatic reductive amination of p-hydroxy- and phenylpyruvic acids as a method of synthesis of L-tyrosine and L-phenylalanine labelled with deuterium and tritium>, HPLC of Formula: 606-68-8, the main research area is enzymic reductive amination hydroxy phenylpyruvic acid labeled tyrosine phenylalanine.

We report the synthesis of isotopomers of L-phenylalanine and L-tyrosine selectively labeled with hydrogen isotopes in the 2-position of the side chain. The deuterium or tritium label was introduced using reductive amination activity of enzyme L-phenylalanine dehydrogenase (EC 1.4.1.20). This way p-phenylpyruvic acid was converted into [2-2H]-, [2-3H]-, and doubly labeled [2-2H/3H]-isotopomers of L-phenylalanine, using deuteriated, tritiated, and mixed (DTO) incubation media, resp. Similarly, p-hydroxyphenylpyruvic acid was converted into [2-2H]-, [2-3H]-, and [2-2H/3H]-L-tyrosine. Deuterium labeled isotopomers of L-phenylalanine and L-tyrosine can be used as markers in the investigation of abnormal metabolism of these amino acids observed in patients with inborn genetic diseases such as phenylketonuria and tyrosinemia.

Nukleonika published new progress about Homo sapiens. 606-68-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C21H27N7Na2O14P2, HPLC of Formula: 606-68-8.

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

Tanaka, Ken; Nishida, Goushi; Wada, Azusa; Noguchi, Keiichi published the artcile< Enantioselective synthesis of axially chiral phthalides through cationic [RhI(H8-BINAP)]-catalyzed cross alkyne cyclotrimerization>, Synthetic Route of 139139-93-8, the main research area is enantioselective synthesis axially chiral phthalide cationic rhodium alkyne cyclization; crystal mol structure axially chiral chlorophenyl hydroxymethyl isobenzofuranone preparation; asym synthesis axially chiral isobenzofuranone aryl hydroxymethyl preparation.

Easy access to axially chiral phthalides that bear one or two oxymethylene functionalities is provided by an enantioselective cross alkyne cyclotrimerization in the presence of the cationic complex [RhI[(S)H8-BINAP]]+. The catalyst, [(1,2,5,6-η)-1,5-cyclooctadiene][(1S)-(5,5′,6,6′,7,7′,8,8′-octahydro[1,1′-binaphthalene]-2,2′-diyl)bis[diphenylphosphine]-P,P’]rhodium(1+) tetrafluoroborate(1-), was prepared using [(1S)-5,5′,6,6′,7,7′,8,8′-octahydro[1,1′-binaphthalene]-2,2′-diyl]bis[diphenylphosphine] and bis[(1,2,5,6-η)-1,5-cyclooctadiene]rhodium tetrafluoroborate(1-) as precursors. The axial chirality is introduced during the formation of the benzene ring with high enantioselectivity. For example, the stereoselective cyclotrimerization of 3-(2-methylphenyl)-2-propynoic acid 2-propynyl ester (I) with 2-butyne-1,4-diol diacetate gave (+)-(7R)-5,6-bis[(acetyloxy)methyl]-7-(2-methyl)-1(3H)-isobenzofuranone (II).

Angewandte Chemie, International Edition published new progress about Alkynyl alcohols Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Synthetic Route of 139139-93-8.

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

Aida, Yukimasa; Sugiyama, Haruki; Uekusa, Hidehiro; Shibata, Yu; Tanaka, Ken published the artcile< Rhodium-Catalyzed Asymmetric [2 + 2 + 2] Cycloaddition of α,ω-Diynes with Unsymmetrical 1,2-Disubstituted Alkenes>, Computed Properties of 139139-86-9, the main research area is rhodium catalyzed asym cycloaddition diyne unsym alkene; axial chiral biaryl phosphine rhodium complex cycloaddition catalyst; multicyclic compound enantioselective preparation.

It has been established that a cationic rhodium(I)/axially chiral biaryl bisphosphine complex catalyzes the asym. [2 + 2 + 2] cycloaddition of α,ω-diynes with electron-rich and unstrained unsym. 1,2-disubstituted alkenes to give chiral multicyclic compounds with good yields and ee values. Interestingly, enantioselectivity highly depends on the structures of α,ω-diynes used presumably due to the presence of two distinct reaction pathways.

Organic Letters published new progress about [2+2+2] Cycloaddition reaction (stereoselective). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Computed Properties of 139139-86-9.

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

Xiao, Xiong; Yu, Zhi-Xiang published the artcile< Co-Catalyzed Asymmetric Intramolecular [3+2] Cycloaddition of Yne-Alkylidenecyclopropanes and its Reaction Mechanism>, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is alkylidenecyclopropanes cobalt catalyst enantioselective cycloaddition mechanism DFT; carbocycle stereoselective preparation; alkylidenecyclopropanes; carbocycles; cobalt; homogeneous catalysis; reaction mechanisms.

Developing new transition metal-catalyzed asym. cycloadditions for the synthesis of five-membered carbocycles (FMCs) is a research frontier in reaction development due to the ubiquitous presence of chiral FMCs in various functional mols. Reported here is our discovery of a highly enantioselective intramol. [3+2] cycloaddition of yne-alkylidenecyclopropanes (yne-ACPs) to bicyclo[3.3.0]octadiene, e.g., I, and bicyclo[4.3.0]nonadiene mols. using a cheap Co catalyst and com. available chiral ligand (S)-Xyl-BINAP. This reaction avoids the use of precious Pd and Rh catalysts, which are usually the choices for [3+2] reactions with ACPs. The enantiomeric excess in the present reaction can be up to 92%. Cationic cobalt(I) species was suggested by experiments as the catalytic species. DFT calculations showed that this [3+2] reaction starts with oxidative cyclometallation of alkyne and ACP, followed by ring opening of the cyclopropyl (CP) group and reductive elimination to form the cycloadduct. This mechanism is different from previous [3+2] reactions of ACPs, which usually start from CP cleavage, not from oxidative cyclization.

Chemistry – A European Journal published new progress about [3+2] Cycloaddition reaction catalysts. 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.

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

Shibata, Takanori; Otomo, Mayumi; Endo, Kohei published the artcile< Enantioselective intramolecular [2+2+2] cycloaddition of dienynes for the construction of adjacent three chiral centers>, Synthetic Route of 139139-93-8, the main research area is dienyne enantioselective intramol cycloaddition rhodium catalyst; chiral multicyclic cyclohexene asym synthesis.

A chiral Rh catalyst realized the intramol. [2+2+2] cycloaddition of yne-ene-enes, and chiral multicyclic cyclohexenes with adjacent three chiral centers were afforded with high to excellent ee.

Synlett published new progress about Alkadienes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Synthetic Route of 139139-93-8.

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

Cera, Gianpiero; Chiarucci, Michel; Mazzanti, Andrea; Mancinelli, Michele; Bandini, Marco published the artcile< Enantioselective gold-catalyzed synthesis of polycyclic indolines>, Quality Control of 325168-88-5, the main research area is furoindoline enantioselective preparation; dihydropyranylindoline enantioselective preparation; hydroxyalkynylindole preparation intramol cyclization gold catalyst.

The synthesis of architecturally complex polycyclic fused indolines is achieved in a chemo-, regio-, and stereodefined manner, via an enantioselective gold-catalyzed cascade hydroindolination/iminium trapping synthetic sequence. Highly functionalized tetracyclic fused furoindolines and dihydropyranylindolines are synthesized in moderate to good yields and enantiomeric excesses of up to 87%.

Organic Letters published new progress about Chiral ligands Role: CAT (Catalyst Use), USES (Uses). 325168-88-5 belongs to class chiral-phosphine-ligands, and the molecular formula is C48H50P2, Quality Control of 325168-88-5.

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