Day: October 17, 2022

Trost, Barry M.; Schroeder, Gretchen M.; Kristensen, Jesper published the artcile< Palladium-catalyzed asymmetric allylic alkylation of α-aryl ketones>, Related Products of 152140-65-3, the main research area is ketone alpha aryl palladium catalyzed asym allylic alkylation; cycloalkanone allylic quaternary asym synthesis.

Quaternary centers were created asym. in high enantiomeric excesses by the proper choice of ligand and metal cation in the Pd-catalyzed asym. allylic alkylation of cyclic α-aryl ketones, e.g. I (n = 1-3; R = Ph, 4-FC6H4, 2-furyl, 2-naphthalenyl, etc.), with formation of allyl cycloalkanones, e.g. II. A broad range of ketone enolates can be tolerated in the reaction, as illustrated by the synthesis of conformationally constrained β-tetralone in 96% ee.

Angewandte Chemie, International Edition published new progress about Allylic alkylation catalysts, stereoselective. 152140-65-3 belongs to class chiral-phosphine-ligands, and the molecular formula is C54H42N2O2P2, Related Products of 152140-65-3.

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

Murai, Masahito; Takeshima, Hirotaka; Morita, Haruka; Kuninobu, Yoichiro; Takai, Kazuhiko published the artcile< Acceleration effects of phosphine ligands on the rhodium-catalyzed dehydrogenative silylation and germylation of unactivated C(sp3)-H bonds>, Synthetic Route of 139139-86-9, the main research area is diphosphine ligand rhodium catalysis dehydrogenative silylation germylation.

The current work describes the marked rate of acceleration caused by phosphine ligands on the rhodium-catalyzed dehydrogenative silylation and germylation of unactivated C(sp3)-H bonds. The reactivity was affected by the steric and electronic nature of the phosphine ligands. The use of the bulky and electron-rich diphosphine ligand (R)-DTBM-SEGPHOS was highly effective to yield the dehydrogenative silylation products selectively in the presence of a hydrogen acceptor. An appropriate choice of C2-sym. chiral diphosphine ligand enables the asym. dehydrogenative silylation via the enantioselective desymmetrization of the C(sp3)-H bond. The unprecedented catalytic germylation of C(sp3)-H bonds with dehydrogenation was also examined with the combination of the rhodium complex and a wide bite angle diphosphine ligand to provide the corresponding 2,3-dihydrobenzo[b]germoles in good yield.

Journal of Organic Chemistry published new progress about Cyclization (silylative). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Synthetic Route 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

Brusoe, Andrew T.; Alexanian, Erik J. published the artcile< Rhodium(I)-Catalyzed Ene-Allene-Allene [2+2+2] Cycloadditions: Stereoselective Synthesis of Complex trans-Fused Carbocycles>, Application In Synthesis of 139139-86-9, the main research area is eneallene allene rhodium catalyzed cycloaddition; hydrindane decalin stereoselective preparation four contiguous stereocenters; fused carbocycle stereoselective preparation.

The rhodium-catalyzed [2+2+2] cycloaddition of ene-allenes with allenes was utilized for the construction of a variety of trans-fused hydrindanes and decalins in a highly convergent manner, with three σ bonds, two rings, and up to four contiguous stereocenters generated in a regio- and stereoselective fashion.

Angewandte Chemie, International Edition published new progress about Allenes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Application In Synthesis 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

Wang, Yan-zi; Zhao, Zhi-ping; Li, Man-feng; Chen, Yong-zhen; Liu, Wen-fang published the artcile< Development of a hollow fiber membrane micro-reactor for biocatalytic production of formate from CO2>, Safety of ((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 hollow fiber membrane bioreactor formate carbon dioxide.

A hollow fiber membrane (HFM) micro-reactor was developed for the conversion of CO2 to formate for the first time by combining hydrophobic polymer HFMs as a gas distributor and modified polyethylene (PE) HFMs for enzyme immobilization in the same module. The effects of the ventilation mode, polymer type and parameters of bubbling membrane, gas velocity and configurational parameters of the HFM module on the reaction were investigated. Using HFM for aeration, the specific activity of enzyme increased, and the Michaelis constant decreased remarkably. For most membranes investigated, when the porosity and pore size of the aerating membrane increased, the reaction rate initially increased and later decreased. The maximum rate was achieved with PE when the porosity was 50% and the pore size was 0.625 μm. For the membranes made of the same type of polymer, a higher value for the contact angle corresponded with a higher reaction rate. Upgrading the number of bubbling HFMs and packing d. intensified the reaction. The optimum upstream gas velocity decreased as the bubbling HFM number increased. The HFM number for bearing enzyme and the height-diameter ratio of the module had no significant effects on the reaction. HFM-attached enzyme showed excellent reusability and storage stability.

Journal of Membrane Science published new progress about Biochemical reaction kinetics. 606-68-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C21H27N7Na2O14P2, Safety of ((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.

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

Santos, Erika Cristina dos; Fonseca, Aldcejam Martins da Junior; Lima, Camila Bruna de; Ispada, Jessica; Silva, Joao Vitor Alcantara da; Milazzotto, Marcella Pecora published the artcile< Less is more: Reduced nutrient concentration during in vitro culture improves embryo production rates and morphophysiology of bovine embryos>, SDS of cas: 606-68-8, the main research area is bovine embryo embryonic culture supplementation media; Bovine; Culture media; ECS media; Embryo.

Reproducing the environment to which the embryo is naturally exposed may be an alternative to improve viability of embryos produced in vitro. In the first part of this work, we describe a novel culture media, namely Embryonic Culture Supplementation (ECS100). The composition of this media was based on the contents of carbohydrates and amino acids found in oviductal and uterine fluids. Because it was a new formulation, we investigated the performance of ECS100 in comparison with conventionally used SOFaa, and possible benefits to embryo development. Embryo production rates (cleavage, morula and blastocyst conversion, blastocyst and hatching rates) and morphophysiol. parameters (total cell number, cell allocation, Mitochondrial membrane potential (MMP), Reactive Oxygen Species (ROS), NADH, FAD+ and ATP content) were similar between ECS100 and SOFaa. Next, we tested if a reduction of ECS100 concentration could pos. contribute to embryo viability by resembling the more dynamic availability of nutrients that reach the embryos in vivo. Therefore, embryos were cultured in ECS100 or in its serial dilution (ECS75, 50 and 25). Despite the fact that the lowest concentration (ECS25) still supported blastocyst formation, halving the concentration of metabolites (ECS50) actually improved embryo production rates. Thus, embryos produced in ECS100 or ECS50 were submitted to further analyzes on Days 4 and 7. Embryos cultured in ECS50 presented better developmental rates and morphophysiol. profile than embryos cultured in ECS100. Addnl., physiol. traits (MMP, ROS and NADH levels) of embryos cultured in ECS50 presented the expected pattern for embryos produced in vivo. In conclusion, we presented a novel, more personalized and effective culture media for bovine IVP embryos. And although the ECS media formulation was based on the contents of female reproductive fluids, it is worth mentioning that adaptations must be specifically directed for in vitro conditions rather than reproduced exactly from in vivo state.

Theriogenology published new progress about Adaptation, animal (zygote). 606-68-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C21H27N7Na2O14P2, SDS of cas: 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

Sekine, Keisuke; Akaishi, Dai; Konagaya, Kakeru; Ito, Shigekazu published the artcile< Copper-Catalyzed Enantioselective Hydrosilylation of gem-Difluorocyclopropenes Leading to a Stereochemical Study of the Silylated gem-Difluorocyclopropanes>, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is cyclopropene difluoro asym hydrosilylation silylboronate preparation chiral arylcyclopropane; copper chiral diphosphine monophosphine catalyst asym hydrosilylation difluorocyclopropene; asymmetric synthesis; copper catalysis; cyclopropanes; fluorine; racemization.

1-Aryl-2,2-difluorocyclopropenes ArC3HF2 undergo asym. hydrosilylation with pinBSiPhMe2 catalyzed by copper(I) complexes with mono- and bidentate chiral phosphines, affording trans-silylcyclopropanes ArCH(CF2)CHSiPhMe2 with up to 95% ee, which upon desilylation gave chiral 2-aryl-1,1-difluorocyclopropanes. Optically active cyclopropanes have been widely investigated especially from the views of pharmaceutical and agrochem. industries, and substituting one of the methylenes with the difluoromethylene unit should be promising for developing novel biol. relevant compounds and functional materials. In this paper, the copper-catalyzed enantioselective hydrosilylation of gem-difluorocyclopropenes to provide the corresponding chiral gem-difluorocyclopropanes is presented. The use of copper(I) chloride, chiral ligands including bidentate BINAPs and monodentate phosphoramidites, and silylborane Me2PhSi-Bpin accompanying sodium tert-butoxide in methanol was appropriate for the enantioselective hydrosilylation of the strained C:C double bond, and the resultant chiral difluorinated three-membered ring was unambiguously characterized. Subsequent activation of the silyl groups in enantio-enriched gem-difluorocyclopropanes showed substantial reduction of the enantiopurity, indicating cleavage of the distal C-C bond leading to the transient acyclic intermediates.

Chemistry – A European Journal published new progress about Chiral ligands Role: CAT (Catalyst Use), USES (Uses) (chiral phosphines). 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

Felix, Ryan J.; Weber, Dieter; Gutierrez, Osvaldo; Tantillo, Dean J.; Gagne, Michel R. published the artcile< A gold-catalysed enantioselective Cope rearrangement of achiral 1,5-dienes>, Computed Properties of 325168-88-5, the main research area is gold catalysis enantioselective cope rearrangement achiral dienes.

Since the discovery of the Cope rearrangement in the 1940s, no asym. variant of the rearrangement of achiral 1,5-dienes has emerged, despite the successes that have been achieved with its heteroatom variants (Claisen, aza-Cope, and so on). This article reports the first example of an enantioselective Cope reaction that starts from an achiral diene. The new gold(I) catalyst derived from double Cl–abstraction of ((S)-3,5-xylyl-PHANEPHOS(AuCl)2), has been developed for the sigmatropic rearrangement of alkenyl-methylenecyclopropanes. The reaction proceeds at low temperature and the synthetically useful vinylcyclopropane products are obtained in high yield and enantioselectivity. D. functional theory calculations predict that: (1) the reaction proceeds via a cyclic carbenium ion intermediate, (2) the relief of strain in the methylenecyclopropane moiety provides the thermodn. driving force for the rearrangement and (3) metal complexation of the transition-state structure lowers the rearrangement barriers.

Nature Chemistry published new progress about [3,3]-Sigmatropic rearrangement. 325168-88-5 belongs to class chiral-phosphine-ligands, and the molecular formula is C48H50P2, Computed Properties 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

Tanaka, Ken; Sagae, Hiromi; Toyoda, Kazuki; Hirano, Masao published the artcile< Enantioselective synthesis of planar-chiral metacyclophanes through cationic Rh(I)/modified-BINAP-catalyzed inter- and intramolecular alkyne cyclotrimerizations>, Safety of (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is enantioselective synthesis chiral metacyclophane rhodium BINAP catalyst alkyne cyclotrimerization.

We have achieved the first catalytic enantioselective synthesis of planar-chiral metacyclophanes by means of cationic Rh(I)/(S)-xyl-H8-BINAP or (R)-H8-BINAP complex-catalyzed inter- and intramol. alkyne cyclotrimerizations. This highly enantioselective catalysis represents a versatile new method for the preparation of planar-chiral metacyclophanes.

Tetrahedron published new progress about Cyclotrimerization. 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Safety of (R)-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

Goulioukina, Nataliya S.; Shergold, Ilya A.; Rybakov, Victor B.; Beletskaya, Irina P. published the artcile< One-Pot Two-Step Synthesis of Optically Active α-Amino Phosphonates by Palladium-Catalyzed Hydrogenation/Hydrogenolysis of α-Hydrazono Phosphonates>, Category: chiral-phosphine-ligands, the main research area is chiral hydrazono amino phosphonate palladium catalyzed enantioselective hydrogenation; crystal structure chiral hydrazono amino phosphonate; mol structure chiral hydrazono amino phosphonate; amino phosphonate chiral preparation optical activity.

An efficient and convenient 1-pot procedure for the stereoselective catalytic synthesis of ring-substituted [amino(phenyl)methyl]phosphonates was developed. The enantioselective hydrogenation of easily available diisopropyl (Z)-[aryl(phenylhydrazono)methyl]phosphonates using Pd(II) acetate as a precatalyst, (R)-2,2′-bis(diphenylphosphino)-5,5′-dichloro-6,6′-dimethoxy-1,1′-biphenyl [(R)-Cl-MeO-BIPHEP] as a ligand, and (1S)-(+)-10-camphorsulfonic acid as an activator in a mixture of 2,2,2-trifluoroethanol and CH2Cl2 at ambient temperature gave corresponding [aryl(2-phenylhydrazino)methyl]phosphonates. The subsequent cleavage of the N-N bond was accomplished with H2 after the addition of Pd on C and MeOH into crude reaction mixture to afford the optically active [amino(aryl)methyl]phosphonates. The method is operationally simple and provides an appreciable enantioselectivity up to 98% ee.

Advanced Synthesis & Catalysis published new progress about Crystal structure. 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Category: chiral-phosphine-ligands.

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

Li, Min; Li, Bin; Xia, Hong-Feng; Ye, Danru; Wu, Jing; Shi, Yifeng published the artcile< Mesoporous silica KIT-6 supported superparamagnetic CuFe2O4 nanoparticles for catalytic asymmetric hydrosilylation of ketones in air>, Product Details of C44H40P2, the main research area is silica copper iron oxide nanoparticle catalyst ketone asym hydrosilylation.

A diverse range of prochiral ketones were reduced in air with high yields and good-to-excellent enantioselectivities (up to 97% ee) in the presence of a heterogeneous catalyst system, which was in situ formed from catalytic amounts of superparamagnetic CuFe2O4 nanoparticles supported on mesoporous silica KIT-6 and non-racemic dipyridylphosphine ligand, the stoichiometric hydride donor polymethylhydrosiloxane (PMHS) as well as certain amounts of additives. The magnetically separable catalysts could be efficiently reused 4 times without apparent loss of both the activity and enantioselectivity.

Green Chemistry published new progress about Catalyst supports. 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Product Details of C44H40P2.

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