Day: February 23, 2023

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

Gold(I)-Catalyzed Stereoselective Olefin Cyclopropanation was written by Johansson, Magnus J.;Gorin, David J.;Staben, Steven T.;Toste, F. Dean. And the article was included in Journal of the American Chemical Society in 2005.Application In Synthesis of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine This article mentions the following:

A triphenylphosphinegold(I)-catalyzed cyclopropanation of olefins using propargyl esters as gold(I)-carbene precursors is reported. This reaction provided the basis for the use of a DTBM-SEGPHOS gold(I) complex as a catalyst in the enantioselective (up to 94% ee) preparation of vinylcyclopropanes with high cis-selectivity. In the experiment, the researchers used many compounds, for example, (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9Application In Synthesis 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. 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. Effective chiral catalysts for nucleophilic phosphine catalysis are scarce, seriously limiting the development of asymmetric variants. Application In Synthesis of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Catalytic Enantioselective Synthesis of γ-Lactams with β-Quaternary Centers via Merging of C-C Activation and Sulfonyl Radical Migration was written by Yu, Xuan;Zhang, Zining;Dong, Guangbin. And the article was included in Journal of the American Chemical Society in 2022.Application of 133545-16-1 This article mentions the following:

To expand the repertoire of C-C activation, here the discovery of a Rh-catalyzed enantioselective C-C activation involving migration of a sulfonyl radical were described. This reaction directly transforms cyclobutanones containing a sulfonamide-tethered 1,3-diene moiety into γ-lactams containing a β-quaternary center with excellent enantioselectivity. This unusual process involved cleavage of C-C and N-S bonds and subsequent formation of C-N and C-S bonds. The reaction also exhibited broad functional group tolerance and a good substrate scope. A combined exptl. and computational mechanistic study suggested that the reaction goes through a Rh(I)-mediated oxidative addition into the cyclobutanone C-C bond followed by a Rh(III)-triggered N-S bond homolysis and sulfonyl radical migration. In the experiment, the researchers used many compounds, for example, (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) (cas: 133545-16-1Application of 133545-16-1).

(R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) (cas: 133545-16-1) belongs to chiral phosphine ligands. Generally, the efficiency of nucleophilic phosphine catalysis often depends on the nature of the tertiary phosphine. Trivalent phosphorus compounds called phosphines have a tetrahedral electron-group geometry which makes them structurally analogous to amines.Application of 133545-16-1

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

A Practical, Enantioselective Synthesis of the Fragrances Canthoxal and Silvial, and Evaluation of Their Olfactory Activity was written by Beghetto, Valentina;Scrivanti, Alberto;Bertoldini, Matteo;Aversa, Manuela;Zancanaro, Aurora;Matteoli, Ugo. And the article was included in Synthesis in 2015.Computed Properties of C74H104O6P2 This article mentions the following:

Fragrances (S)-(+)-canthoxal, (R)-(-)-canthoxal [i.e., (S)-(+)-3-(4-methoxyphenyl)-2-methylpropanal, (R)-(-)-3-(4-methoxyphenyl)-2-methylpropanal] and (+)-Silvial and (-)-Silvial were synthesized in high enantiopurity by a simple four-step strategy starting from the com. available 4-substituted benzaldehydes. The key synthetic step is the catalytic asym. hydrogenation of the appropriate 3-aryl-2-(methyl)acrylic acid which has been carried out employing an in situ prepared ruthenium/axially chiral phosphine catalyst (up to 98% ee). The olfactory activity of the single enantiomers was evaluated. Under optimized conditions the synthesis of the target compounds was achieved using 1,1′-[(1S)-6,6′-dimethoxy[1,1′-biphenyl]-2,2′-diyl]bis[1,1-bis[3,5-bis(1,1-dimethylethyl)-4-methoxyphenyl]phosphine] [i.e., (S)-3,5-di-tert-butyl-4-MeOBIPHEP] and bis(η⁶-benzene)di-μ-(chloro)dichlorodiruthenium as ligand-catalyst combination. The tilte compounds thus formed included (αS)-5-methoxyα-methylbenzenepropanal [i.e., (+)-(S)-canthoxal] and (αR)-5-methoxyα-methylbenzenepropanal [i.e., (-)-(R)-canthoxal]. Silvial enantiomers included (-)-α-methyl-4-(2-methylpropyl)benzenepropanal [i.e., (-)-Silvial] and (+)-α-methyl-4-(2-methylpropyl)benzenepropanal [i.e., (+)-Silvial]. Other catalysts included (1S,1′S)-1,1′-bis[bis(4-methoxy-3,5-dimethylphenyl)phosphino]-2,2′-bis[(R)-(dimethylamino)phenylmethyl]ferrocene [(RS)-MandyPhos], 1,1′-[(1S)-6,6′-dimethoxy[1,1′-biphenyl]-2,2′-diyl]bis[1,1-diphenylphosphine [(S)-MeOBIPHEP], 1,1′-[(1R)-[1,1′-binaphthalene]-2,2′-diyl]bis[1,1-diphenylphosphine] [(R)-BINAP]. 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: 352655-61-9Computed Properties of C74H104O6P2).

(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. 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. Trivalent phosphorus compounds called phosphines have a tetrahedral electron-group geometry which makes them structurally analogous to amines.Computed Properties of C74H104O6P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Palladium-catalyzed DYKAT of vinyl epoxides: Enantioselective total synthesis and assignment of the configuration of (+)-broussonetine G was written by Trost, Barry M.;Horne, Daniel B.;Woltering, Michael J.. And the article was included in Angewandte Chemie, International Edition in 2003.HPLC of Formula: 174810-09-4 This article mentions the following:

A potential general approach to potent N-heterocyclic glycosidase inhibitors is illustrated by the first total synthesis of (+)-broussonetine G. The key transformation of the synthesis relies on two successive palladium-catalyzed asym. allylic alkylations of butadiene monoxide with a nitrogen nucleophile to construct the pyrrolidine core. In the experiment, the researchers used many compounds, for example, N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4HPLC of Formula: 174810-09-4).

N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4) belongs to chiral phosphine ligands. At present, the synthesis of new chiral phosphines designed specifically for nucleophilic organocatalysis remains a significant challenge. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.HPLC of Formula: 174810-09-4

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Nonenzymatic kinetic resolution of secondary alcohols: enantioselective S_N2 displacement of hydroxy groups by halogens in the presence of chiral BINAP was written by Sekar, Govindasamy;Nishiyama, Hisao. And the article was included in Journal of the American Chemical Society in 2001.Quality Control of (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) This article mentions the following:

Cyclic secondary alcs. I (R = Ph, 2-MeC₆H₄, 3-MeC₆H₄, 4-MeC₆H₄, 4-MeOC₆H₄, 1-naphthyl, 2-naphthyl, cyclohexyl), phenylcyclooctanol II, and 1-phenyl-2-octadecanol undergo kinetic resolution by stereoselective nucleophilic displacement of secondary alcs. with chlorides in the presence of (S)-BINAP to give unreacted alcs. such as III in 82-97% yields and 69-98% ee and the inverted secondary chlorides IV in 56-94% ee. E.g., dehydrated THF was added to a mixture of I (R = Ph), 1 equivalent N-chlorosuccinimide, and 0.3 equivalent (S)-BINAP and the mixture stirred until the solution became clear; workup and chromatog. yielded (1R,2S)-III in 40% yield and 85% ee and (1R,2R)-IV in 42% yield and 89% ee in addition to the P,P’-dioxide of (S)-BINAP which was recovered in 92%. The enantioselectivity of the resolution was highly dependent upon the solvent used and the amount of chlorinating agent used; THF was the optimal solvent for the process and N-chlorosuccinimide as the chlorinating agent. In the experiment, the researchers used many compounds, for example, (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) (cas: 37002-48-5Quality Control of (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine)).

(((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) (cas: 37002-48-5) belongs to chiral phosphine ligands. Although many reactions require more nucleophilic trialkylphosphines as catalysts, only a few chiral trialkylphosphines are available. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.Quality Control of (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine)

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis