Month: February 2023

Ring Expansion of Silacyclobutanes with Allenoates to Selectively Construct 2- or 3-(E)-Enoate-Substituted Silacyclohexenes was written by Tang, Xiaoxiao;Zhang, Yan;Tang, Yulang;Li, Yi;Zhou, Jiajing;Wang, Duyang;Gao, Lu;Su, Zhishan;Song, Zhenlei. And the article was included in ACS Catalysis in 2022.Formula: C26H28FeNP This article mentions the following:

Silacycle is one of the most essential core frameworks in Si-containing functional mols. However, the structural diversity of silacycles was largely limited due to the lack of general synthetic methods. Here, the authors report an efficient synthesis of exo-cyclic enoate-substituted silacyclohexenes by the ring expansion of silacyclobutanes with allenoates. The reaction proceeds with two regioselectivities during Si-C bond insertion. In the presence of the Pd/PR₃ catalyst, unsubstituted allenoates undergo β, γ-insertion to form a Si-Cβ bond, giving 2-(E)-enoate-substituted silacyclohexenes. In this pathway, a chiral phosphoramidite ligand was used to construct the stereogenic Si center enantioselectively. In the 2nd pathway, in the presence of the PtCl₂ catalyst, α-substituted allenoates undergo γ, β-insertion to form a Si-Cγ bond, leading to 3-(E)-enoate-substituted silacyclohexenes. The control experiments and d. functional theory calculations were performed to understand the regio- and stereochem. outcome of both Pd- and Pt-catalyzed ring expansion reactions. In the experiment, the researchers used many compounds, for example, (R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine (cas: 55700-44-2Formula: C26H28FeNP).

(R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine (cas: 55700-44-2) belongs to chiral phosphine ligands. Phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles. Asymmetric catalytic performance is determined not only by the metal center but also by the chiral ligand selected.Formula: C26H28FeNP

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Sequence of Intramolecular Carbonylation and Asymmetric Hydrogenation Reactions: Highly Regio- and Enantioselective Synthesis of Medium Ring Tricyclic Lactams was written by Lu, Shui-Ming;Alper, Howard. And the article was included in Journal of the American Chemical Society in 2008.Category: chiral-phosphine-ligands This article mentions the following:

The intramol. cyclocarbonylation reaction of (aminoaryloxy)-functionalized arylalkynes and analogs I (X = N, CH, CCl; Y = O, NMe, OCH₂, OCH₂CH₂; R¹ = H, Me, OMe, CN, CF₃, Cl, MeCO; R² = H, Me, CO₂Me; R³ = H, Cl, Me, CO₂Me) with palladium-complexed dendrimers on silica is a very effective method for the regioselective synthesis of methylene 8-, 9-, and 10-membered rings II. The heterogeneous dendritic catalysts were easily recovered by simple filtration and reused for up to 10 cycles with only a slight loss of activity. Asym. hydrogenation of the resulting unsaturated heterocycles II afforded optically active tricyclic lactams III in excellent yields and in high enantiomeric excess. This process can tolerate a wide array of functional groups, including halide, ether, nitrile, ketone, and ester. Moreover, the variation of heteroatom on the rings does not have any influence on the efficiency and enantioselectivity of the reaction. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Category: chiral-phosphine-ligands).

(2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2) belongs to chiral phosphine ligands. During the past two decades, tertiary phosphine catalysts have been applied extensively in a wide range of carbon–carbon and carbon–heteroatom bond-forming transformations. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.Category: chiral-phosphine-ligands

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Enantioselective Synthesis of 3,3-Disubstituted Oxindoles through Pd-Catalyzed Cyanoamidation was written by Yasui, Yoshizumi;Kamisaki, Haruhi;Takemoto, Yoshiji. And the article was included in Organic Letters in 2008.Quality Control of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine This article mentions the following:

The first enantioselective intramol. cyanoamidation of olefins provides quick access to a variety of 3,3-disubstituted oxindoles. The combination of Pd(dba)₂, optically active phosphoramidite I, and N,N-dimethylpropylene urea (DMPU) in decalin were found to be the best conditions. In the experiment, the researchers used many compounds, for example, (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9Quality Control of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine).

(S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9) belongs to chiral phosphine ligands. At present, the synthesis of new chiral phosphines designed specifically for nucleophilic organocatalysis remains a significant challenge. Indeed, very little research on chiral tertiary phosphine-catalyzed asymmetric reactions occurred prior to the year 2000.Quality Control of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Enantioselective Construction of Acyclic Quaternary Carbon Stereocenters: Palladium-Catalyzed Decarboxylative Allylic Alkylation of Fully Substituted Amide Enolates was written by Starkov, Pavel;Moore, Jared T.;Duquette, Douglas C.;Stoltz, Brian M.;Marek, Ilan. And the article was included in Journal of the American Chemical Society in 2017.Synthetic Route of C52H44N2O2P2 This article mentions the following:

Authors report a divergent and modular protocol for the preparation of acyclic mol. frameworks containing newly created quaternary carbon stereocenters. Central to this approach is a sequence composed of a (1) regioselective and -retentive preparation of allyloxycarbonyl-trapped fully substituted stereodefined amide enolates and of a (2) enantioselective palladium-catalyzed decarboxylative allylic alkylation reaction using a novel bisphosphine ligand. In the experiment, the researchers used many compounds, for example, N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4Synthetic Route of C52H44N2O2P2).

N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4) belongs to chiral phosphine ligands. Many phosphine-catalyzed reactions have been developed for the syntheses of various biologically important acyclic and cyclic molecules. Asymmetric variants of these reactions have evolved relatively slowly. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.Synthetic Route of C52H44N2O2P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

An efficient copper-aluminum hydrotalcite catalyst for asymmetric hydrosilylation of ketones at room temperature. [Erratum to document cited in CA149:246243] was written by Kantam, M. Lakshmi;Laha, Soumi;Yadav, Jagjit;Likhar, Pravin R.;Sreedhar, B.;Jha, Shailendra;Bhargava, Suresh;Udayakiran, M.;Jagadeesh, B.. And the article was included in Organic Letters in 2008.Quality Control of (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) This article mentions the following:

The Supporting Information Section contained errors in the optical rotation, concentration, H NMR chem. shift values, C NMR chem. shift values, HPLC retention times, and HPLC spectra. The corrected version of the Supporting Information is available online. In the experiment, the researchers used many compounds, for example, (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) (cas: 133545-16-1Quality Control of (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine)).

(R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) (cas: 133545-16-1) belongs to chiral phosphine ligands. At present, the synthesis of new chiral phosphines designed specifically for nucleophilic organocatalysis remains a significant challenge. Effective chiral catalysts for nucleophilic phosphine catalysis are scarce, seriously limiting the development of asymmetric variants. Quality Control of (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine)

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Rigid P-Chiral Phosphine Ligands with tert-Butylmethylphosphino Groups for Rhodium-Catalyzed Asymmetric Hydrogenation of Functionalized Alkenes was written by Imamoto, Tsuneo;Tamura, Ken;Zhang, Zhenfeng;Horiuchi, Yumi;Sugiya, Masashi;Yoshida, Kazuhiro;Yanagisawa, Akira;Gridnev, Ilya D.. And the article was included in Journal of the American Chemical Society in 2012.Reference of 1355162-85-4 This article mentions the following:

Both enantiomers of 2,3-bis(tert-butylmethylphosphino)quinoxaline (QuinoxP*), 1,2-bis(tert-butylmethylphosphino)benzene (BenzP*), and 1,2-bis(tert-butylmethylphosphino)-4,5-(methylenedioxy)benzene (DioxyBenzP*) were prepared in short steps from enantiopure (S)- and (R)-tert-butylmethylphosphine-boranes as the key intermediates. All of these ligands were crystalline solids and were not readily oxidized on exposure to air. Their rhodium complexes exhibited excellent enantioselectivities and high catalytic activities in the asym. hydrogenation of functionalized alkenes, such as dehydroamino acid derivatives and enamides. The practical utility of these catalysts was demonstrated by the efficient preparation of several chiral pharmaceutical ingredients having an amino acid or a secondary amine component. A rhodium complex of the structurally simple ligand BenzP* was used for the mechanistic study of asym. hydrogenation. Low-temperature NMR studies together with DFT calculations using Me α-acetamidocinnamate as the standard model substrate revealed new aspects of the reaction pathways and the enantioselection mechanism. In the experiment, the researchers used many compounds, for example, (S,S)-1,2-Bis(t-butylmethylphosphino)benzene (S,S)-BenzP (cas: 1355162-85-4Reference of 1355162-85-4).

(S,S)-1,2-Bis(t-butylmethylphosphino)benzene (S,S)-BenzP (cas: 1355162-85-4) belongs to chiral phosphine ligands. During the past two decades, tertiary phosphine catalysts have been applied extensively in a wide range of carbon–carbon and carbon–heteroatom bond-forming transformations. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Reference of 1355162-85-4

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Histidine and deuterium labeled histidine by asymmetric catalytic reduction with gaseous H₂ or D₂; the role of strong non-coordinating acids was written by Cesarotti, E.;Rimoldi, I.;Zerla, D.;Aldini, G.. And the article was included in Tetrahedron: Asymmetry in 2008.Product Details of 77876-39-2 This article mentions the following:

An efficient and convenient route for the preparation of natural and unnatural histidine by asym. hydrogenation with rhodium-phosphine complexes is described. The reductions were performed in the presence of HBF₄ to generate an essential imidazolyl cation. Stereoselective incorporation of D₂ in the α,β-positions was obtained by catalytic deuteration in the presence of MeOD. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Product Details of 77876-39-2).

(2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2) belongs to chiral phosphine ligands. Phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles. Asymmetric catalytic performance is determined not only by the metal center but also by the chiral ligand selected.Product Details of 77876-39-2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Catalytic Enantioselective Conjugate Alkynylation of α,β-Unsaturated 1,1,1-Trifluoromethyl Ketones with Terminal Alkynes was written by Sanz-Marco, Amparo;Blay, Gonzalo;Munoz, M. Carmen;Pedro, Jose R.. And the article was included in Chemistry – A European Journal in 2016.SDS of cas: 352655-61-9 This article mentions the following:

The first catalytic enantioselective conjugate alkynylation of α,β-unsaturated 1,1,1-trifluoromethyl ketones has been carried out. Terminal alkynes and 1,3-diynes were treated with trifluoromethyl ketones in the presence of a low catalytic load of a Cu^I-MeOBIPHEP complex (2.5 mol %) and triethylamine (10 mol %) to give the corresponding trifluoromethyl ketones bearing a propargylic stereogenic center at the β position with good yields and excellent enantiomeric excesses in most of the cases. No 1,2-addition products were formed under the reaction conditions. The procedure showed broad substrate scope for alkyne, diyne, and enone. A rationale for the observed stereochem. has been provided. Finally, the potential application of the reaction products in the synthesis of chiral tetrahydrofurans bearing a trifluoromethylated quaternary stereocenter has been devised. In the experiment, the researchers used many compounds, for example, (R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl (cas: 352655-61-9SDS of cas: 352655-61-9).

(R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl (cas: 352655-61-9) belongs to chiral phosphine ligands. Generally, the efficiency of nucleophilic phosphine catalysis often depends on the nature of the tertiary phosphine. Effective chiral catalysts for nucleophilic phosphine catalysis are scarce, seriously limiting the development of asymmetric variants. SDS of cas: 352655-61-9

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Toward Asymmetric Synthesis of Pentaorganosilicates was written by van der Boon, Leon J. P.;Fuku-en, Shin-ichi;Slootweg, J. Chris;Lammertsma, Koop;Ehlers, Andreas W.. And the article was included in Topics in Catalysis in 2018.Category: chiral-phosphine-ligands This article mentions the following:

Introducing chiral silicon centers was explored for the asym. Rh-catalyzed cyclization of dihydrosilanes to enantiomerically enriched spirosilanes as targets to enable access to enantiostable pentacoordinate silicates. The steric rigidity required in such systems demands the presence of two naphthyl or benzo[b]thiophene groups. The synthetic approach to the expanded spirosilanes extends Takai’s method (Kuninobu et al. in Angew Chem Int Ed 52(5):1520-1522, 2013) for the synthesis of spirosilabifluorenes in which both a Si-H and a C-H bond of a dihydrosilane are activated by a rhodium catalyst. The expanded dihydrosilanes were obtained from halogenated aromatic precursors. Their asym. cyclization to the spirosilanes were conducted with [Rh(cod)Cl]₂ in the presence of the chiral bidentate phosphine ligands (R)-BINAP, (R)-MeO-BIPHEP, and (R)-SEGPHOS, including derivatives with P-(3,5-t-Bu-4-MeO)-Ph (DTBM) groups. The highest enantiomeric excess of 84% was obtained for 11,11′-spirobi[benzo[b]-naphtho[2,1-d]silole] with the DTBM-SEGPHOS ligand. In the experiment, the researchers used many compounds, for example, (R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl (cas: 352655-61-9Category: chiral-phosphine-ligands).

(R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl (cas: 352655-61-9) belongs to chiral phosphine ligands. Thousands of arylphosphines have been used as chiral ligands for metal-catalyzed asymmetric reactions. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.Category: chiral-phosphine-ligands

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Synthesis, crystal structure, heat capacities and thermodynamic properties of a potential enantioselective catalyst was written by Zeng, Ju-Lan;Yu, Sai-Bo;Cao, Zhong;Yang, Dao-Wu;Sun, Li-Xian;Zhang, Ling;Zhang, Xiong-Fei. And the article was included in Journal of Thermal Analysis and Calorimetry in 2011.Application In Synthesis of (R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine This article mentions the following:

A new potential enantioselective catalyst derived from ferrocene, 1-{(R)-1-[(S)-2-(diphenylphosphino)ferrocenyl]ethyl}benzimidazole (DPFEB), was prepared and its absolute structure was characterized by means of single crystal X-ray diffraction. The molar heat capacity of DPFEB was measured by means of temperature modulated differential scanning calorimetry over the temperature range of 200-530 K, and the thermodn. functions of [H _T – H _298.15] and [S _T – S _298.15] were calculated Further more, thermogravimetry experiment revealed that DPFEB exhibited a three step thermal decomposition process with the final residual of 28.7%. In the experiment, the researchers used many compounds, for example, (R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine (cas: 55700-44-2Application In Synthesis of (R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine).

(R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine (cas: 55700-44-2) belongs to chiral phosphine ligands. Many phosphine-catalyzed reactions have been developed for the syntheses of various biologically important acyclic and cyclic molecules. Asymmetric variants of these reactions have evolved relatively slowly. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.Application In Synthesis of (R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis