Tag: 300-400

Highly Enantioselective Conjugate Additions of Potassium Organotrifluoroborates to Enones by Use of Monodentate Phosphoramidite Ligands was written by Duursma, Ate;Boiteau, Jean-Guy;Lefort, Laurent;Boogers, Jeroen A. F.;De Vries, Andre H. M.;De Vries, Johannes G.;Minnaard, Adriaan J.;Feringa, Ben L.. And the article was included in Journal of Organic Chemistry in 2004.Application of 252288-04-3 This article mentions the following:

The use of phosphoramidite ligands in the rhodium-catalyzed asym. conjugate addition of potassium organotrifluoroborates to various enones in the absence of water is described. A systematic search for effective catalysts has been performed by use of high-throughput screening methods. Initially, reaction conditions and catalyst precursors, and ligand libraries were screened. In the next stage a monodentate ligand combination approach was used, and finally a library of 96 different phosphoramidites was prepared by parallel synthesis using a robot (instant ligand libraries) and these were tested in the vinylation of cyclohexenone (up to 88% enantiomeric excess, ee) and 4-phenyl-3-buten-2-one (up to 42% ee). Arylation of cyclohexenone by use of potassium (phenyl)trifluoroborate gave 3-phenylcyclohexanone with 99% ee. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3Application of 252288-04-3).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) belongs to chiral phosphine ligands. Thousands of arylphosphines have been used as chiral ligands for metal-catalyzed asymmetric reactions. Trivalent phosphorus compounds called phosphines have a tetrahedral electron-group geometry which makes them structurally analogous to amines.Application of 252288-04-3

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Enantioselective Conjugate Addition Catalyzed by a Copper Phosphoramidite Complex: Computational and Experimental Exploration of Asymmetric Induction was written by Ardkhean, Ruchuta;Roth, Philippe M. C.;Maksymowicz, Rebecca M.;Curran, Alex;Peng, Qian;Paton, Robert S.;Fletcher, Stephen P.. And the article was included in ACS Catalysis in 2017.HPLC of Formula: 252288-04-3 This article mentions the following:

The stereochem. role of the phosphoramidite ligand in the asym. conjugate addition of alkylzirconium species to cyclic enones has been established through exptl. and computational studies. Systematic, synthetic variation of the modular ligand established that the configuration of the binaphthol backbone is responsible for absolute stereocontrol, whereas modulation of the amido substituents leads to dramatic variations in the level of asym. induction. Chiral amido substituents are not required for enantioselectivity, leading to the discovery of a new family of easily synthesized phosphoramidites based on achiral amines that deliver equal levels of selectivity to Feringa’s ligand. A linear correlation between the length of the aromatic amido groups and exptl. determined enantioselectivity was uncovered for this class of ligand, which, following an optimization, led to highly selective ligands (up to 94% ee) with naphthyl rather than Ph groups. An electronic effect of sterically similar aromatic substituents was investigated through NMR and DFT studies, showing that electron-rich aryl groups allow better Cu coordination. An interaction between the metal center and an aromatic group is responsible for this enhanced affinity and leads to a more tightly coordinated transition structure, leading to the major enantiomer. These studies illustrate the use of parametric quant. structure-selectivity relationships to generate mechanistic models for asym. induction and catalyst structures that may be further probed by experiment and computation. This integrated approach leads to the rational modification of chiral ligands to achieve enhanced levels of selectivity. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3HPLC of Formula: 252288-04-3).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) 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.HPLC of Formula: 252288-04-3

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

New chiral phosphorus catalysts derived from (S)-binaphthol for highly enantioselective reduction of acetophenone by borane. [Retraction of document cited in CA132:35822] was written by Ma, M. F. P.;Li, K.;Zhou, Z.;Tang, C.;Chan, A. S. C.. And the article was included in Tetrahedron: Asymmetry in 2000.Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine This article mentions the following:

Retraction at the request of the authors who have not been able to reproduce the results reported in the manuscript. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) belongs to chiral phosphine ligands. Generally, the efficiency of nucleophilic phosphine catalysis often depends on the nature of the tertiary phosphine. Indeed, very little research on chiral tertiary phosphine-catalyzed asymmetric reactions occurred prior to the year 2000.Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Tandem Ir-Catalyzed Allylic Substitution Reaction of Allyl Sulfinates and Isomerization was written by Xu, Qing-Long;Dai, Li-Xin;You, Shu-Li. And the article was included in Organic Letters in 2010.Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine This article mentions the following:

An efficient method for the synthesis of trisubstituted vinyl sulfones is reported. Using the [Ir(COD)Cl]₂/phosphoramidite ligand/DBU, trisubstituted vinyl sulfones could be synthesized from allyl sulfinates in high yields as exclusively E isomers. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) 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 phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Enantioselective catalytic conjugate addition of dialkylzinc reagents using copper-phosphoramidite complexes; ligand variation and non-linear effects was written by Arnold, Leggy A.;Imbos, Rosalinde;Mandoli, Alessandro;De Vries, Andre H. M.;Naasz, Robert;Feringa, Ben L.. And the article was included in Tetrahedron in 2000.COA of Formula: C24H22NO2P This article mentions the following:

A variety of new chiral phosphoramidites was synthesized and tested in the copper-catalyzed enantioselective conjugate addition of Et₂Zn to cyclohexenone and chalcone to assess the structural features that are important for stereocontrol. A sterically demanding amine moiety is essential to reach high e.e.’s. Enantioselectivities for chalcones up to 89% and for cyclic enones up to 98% were found. Studies on non-linear effects with the best ligands for both cyclohexenone and chalcone showed clear non-linear effects for both cyclic and acyclic enones. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3COA of Formula: C24H22NO2P).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) belongs to chiral phosphine ligands. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.COA of Formula: C24H22NO2P

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Highly Efficient Rhodium/Monodentate Phosphoramidite Catalyst and Its Application in the Enantioselective Hydrogenation of Enamides and α-Dehydroamino Acid Derivatives was written by Jia, Xian;Li, Xingshu;Xu, Lijin;Shi, Qian;Yao, Xinsheng;Chan, Albert S. C.. And the article was included in Journal of Organic Chemistry in 2003.HPLC of Formula: 252288-04-3 This article mentions the following:

An easily prepared and highly efficient monodentate phosphoramidite ligand (S)-2,2′-O,O-(1,1′-binaphthyl)-dioxo-N,N-diethylphospholidine, derived from BINOL, was examined in the hydrogenation of both enamides H₂C:CR¹NHCOMe (R¹ = Ph, 4-F₃CC₆H₄, 3-MeOC₆H₄, 1-naphthyl, etc.) and α-dehydroamino acid esters R²CH:C(NHR³)CO₂Me (R² = H, Ph, 4-FC₆H₄, 4-MeOC₆H₄, etc.; R³ = MeCO, PhCO). The catalyst provided remarkably high enantioselectivities (up to 99.6% ee for enamides and >99.9% ee for α-dehydroamino acid esters). In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3HPLC of Formula: 252288-04-3).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) 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. HPLC of Formula: 252288-04-3

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Enantioselective 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds catalyzed by rhodium(I)-chiral phosphoramidite complexes was written by Kurihara, Kazunori;Sugishita, Noriyuki;Oshita, Kengo;Piao, Dongguo;Yamamoto, Yasunori;Miyaura, Norio. And the article was included in Journal of Organometallic Chemistry in 2007.Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine This article mentions the following:

A chiral bidentate phosphoramidites I and their rhodium complexes were prepared by esterification of the corresponding linked BINOLs with phosphorous triamides; the complexes exhibit high activity and stereoselectivity in asym. conjugate addition of arylboronic acids to α,β-unsaturated ketones. Reaction of Shibasaki’s linked-(R)-BINOL, (R,R)-3,3”-oxybis(methylene)bis[1,1′-binaphthalene-2,2′-diol], with P(NR₂)₃ gave bis-phosphoramidites I (5a–c; R = Me, Et, ⁱPr); rhodium(I) complexes of 5a [(L)Rh(nbd)]BF₄ and [(L)RhCl] (7a, b) were prepared by complexation of [Rh(nbd)₂]BF₄ and [Rh(coe)Cl], resp. Phosphoramidites 5a–c were used as new ligands for rhodium(I)-catalyzed asym. 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds 2-Cyclohexenone, 2-cyclopentenone, 2-cycloheptenone, (E)-R¹CH:CHCOR² (R¹ = C₅H₁₁, ⁱPr, Ph; R² = Me, Ph, C₆H₁₁) undergo asym. 1,4-addition of ArB(OH)₂ (Ar = Ph, 3-MeOC₆H₄, 4-MeOC₆H₄, 3-ClC₆H₄, 3-FC₆H₄, 4-MeC₆H₄) catalyzed by Rh(I) complexes with ligands I, giving the corresponding 3-substituted ketones with high yields and enantioselectivities up to 99.6 ee. The effects of 5a and Feringa’s monodentate phosphoramidite, (S)-C₂₀H₁₂O₂PNR³R⁴ (4, C₂₀H₁₂ = 1,1′-binaphthalene-2,2′-diyl; R³ = R⁴ = Me, Et, PhCH₂, ⁱPr, R³-R⁴ = (CH₂)₅, CH₂CH₂NHCH₂CH₂; R³, R⁴: Me, Et; Me, Pr; Me, PhCH₂; Me, Ph; Me, ⁱPr; Me, 1-adamantyl; Me, ^tBu) on the yields and enantioselectivities evaluated. The reaction was significantly accelerated in the presence of a base such as KOH and Et₃N, allowing the reaction to be completed at ambient temperature The addition to cyclic enones such as 2-cyclopentenone, 2-cyclohexenone and 2-cycloheptenone at 50° in the presence of an [Rh(coe)₂Cl]₂–4 (R³, R⁴ = Et) resulted in enantioselectivities up to 98%, though it was less effective for acyclic enones (0-70% ee). On the other hand, the complex 7a completed the addition to cyclic enones within 2 h at room temperature in the presence of Et₃N with 86-99% yields and 96-99.8% ee. This catalyst was also effective for acyclic enones, resulting in 62-98% yields and 66-94% ee. The 1,4-additions of arylboronic acids to unsaturated lactones and acyclic esters with rhodium(I)-phosphoramidites complexes were also investigated. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) belongs to chiral phosphine ligands. Although many reactions require more nucleophilic trialkylphosphines as catalysts, only a few chiral trialkylphosphines are available. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Enantioselective Rhodium-Catalyzed Allylic C-H Activation for the Addition to Conjugated Dienes was written by Li, Qian;Yu, Zhi-Xiang. And the article was included in Angewandte Chemie, International Edition in 2011.Application In Synthesis of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine This article mentions the following:

By applying the title transformation, two adjacent sp³ stereogenic centers, one of which is a quaternary carbon center, can be easily formed. This asym. reaction provides easy and efficient access to multifunctionalized tetrahydropyrrole, THF, and cyclopentane compounds In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3Application In Synthesis of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) 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.Application In Synthesis of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Nickel-Catalyzed Asymmetric Ullmann Coupling for the Synthesis of Axially Chiral Tetra-ortho-Substituted Biaryl Dials was written by Chen, Wen-Wen;Zhao, Qian;Xu, Ming-Hua;Lin, Guo-Qiang. And the article was included in Organic Letters in 2010.Name: (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine This article mentions the following:

The first example of nickel-catalyzed asym. Ullmann coupling of bis-ortho-substituted aryl bromides is described. With the chiral BINOL-based monodentate phosphoramidite ligand I, the reaction allows atropoenantioselective synthesis of a series of axially chiral tetra-ortho-substituted biaryl dials. By taking advantage of this asym. Ullmann coupling as a key stereogenic axis-forming reaction, the formal synthesis of (+)-isoschizandrin was accomplished. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3Name: (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) 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. Name: (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Asymmetric allylation of aryl aldehydes: studies on the scope and mechanism of the palladium catalyzed diethylzinc mediated umpolung using phosphoramidite ligands was written by Howell, Gareth P.;Minnaard, Adriaan J.;Feringa, Ben L.. And the article was included in Organic & Biomolecular Chemistry in 2006.Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine This article mentions the following:

Using modular, monodentate phosphoramidite ligands, enantioselective palladium catalyzed diethylzinc mediated allylation of aldehydes was achieved. The scope of the asym. C-C bond formation was investigated with respect to nucleophilic and electrophilic components and an alternative reaction mechanism is proposed based on our findings. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine).

(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) belongs to chiral phosphine ligands. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Effective chiral catalysts for nucleophilic phosphine catalysis are scarce, seriously limiting the development of asymmetric variants. Safety of (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis