Day: February 27, 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