Tag: 440.496

2-(Aminomethyl)pyridine-Phosphine Ruthenium(II) Complexes: Novel Highly Active Transfer Hydrogenation Catalysts was written by Baratta, Walter;Herdtweck, Eberhardt;Siega, Katia;Toniutti, Micaela;Rigo, Pierluigi. And the article was included in Organometallics in 2005.Formula: C29H30P2 This article mentions the following:

Trans,cis-RuCl₂(PPh₃)₂(ampy) (1) and trans-RuCl₂[Ph₂P(CH₂)₄PPh₂](ampy) (2) were prepared in high yield by reaction of RuCl₂(PPh₃)₃ and RuCl₂(PPh₃)[Ph₂P(CH₂)₄PPh₂] with 2-(aminomethyl)pyridine (ampy) at room temperature by PPh₃ displacement. Heating compound 1 in refluxing toluene leads to the isomer cis,cis-RuCl₂(PPh₃)₂(ampy) (3), which was proven to be a good precursor for the preparation of cis-RuCl₂(PP)(ampy) [PP = (S,S)-Chiraphos, 4; Ph₂P(CH₂)₃PPh₂, 5; (S,S)-Skewphos, 6; Ph₂P(CH₂)₄PPh₂, 7; (R,R)-Diop, 8] by displacement of two PPh₃ with the appropriate diphosphine. Cis-RuCl₂(PP)(ampy) [PP = (R,S)-Josiphos, 9; (R,S)-^tBu-Josiphos, 10] were synthesized from RuCl₂(PPh₃)₃ and PP followed by addition of ampy. The chiral complexes 4, 6, 8, 9, and 10 are formed stereoselectively, as inferred by NMR data in solution For the derivatives 7 and 9 the mol. structures were determined by x-ray measurements. The monohydride complex trans,cis-RuHCl(PPh₃)₂(ampy) (11) was prepared from RuHCl(PPh₃)₃ and ampy in heptane by PPh₃ substitution. Compound 11 reacts with Na isopropoxide in toluene, affording the dihydride derivative cis,trans-Ru(H)₂(PPh₃)₂(ampy) (12) via the alkoxide route. The intermediate species cis,cis-Ru(H)₂(PPh₃)₂(ampy) (A) was also characterized by NMR in solution All these complexes are highly efficient transfer hydrogenation catalysts. With cis-RuCl₂(PP)(ampy) a large number of ketones (dialkyl, diaryl, and alkyl-aryl) can be quant. reduced to alcs. in iso-PrOH and in the presence of NaOH (ketone/Ru/NaOH = 2000/1/40) with remarkably high TOF values (up to 400,000 h^-1 at 50% conversion). The derivatives containing chiral diphosphines afforded rapid (TOF > 10⁵ h^-1) and enantioselective (ee up to 94%) reduction of Me-aryl ketones using low loading of catalysts (0.05-0.01 mol %). In the absence of base the dihydride compound 12 catalyzes the transfer hydrogenation of acetophenone. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Formula: C29H30P2).

(2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2) 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. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Formula: C29H30P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Catalytic Asymmetric Synthesis of Quaternary Carbons Bearing Two Aryl Substituents. Enantioselective Synthesis of 3-Alkyl-3-Aryl Oxindoles by Catalytic Asymmetric Intramolecular Heck Reactions was written by Dounay, Amy B.;Hatanaka, Keiko;Kodanko, Jeremy J.;Oestreich, Martin;Overman, Larry E.;Pfeifer, Lance A.;Weiss, Matthew M.. And the article was included in Journal of the American Chemical Society in 2003.Reference of 77876-39-2 This article mentions the following:

A practical sequence involving three consecutive palladium(0)-catalyzed reactions has been developed for synthesizing 3-alkyl-3-aryloxindoles in high enantiopurity. Butenanilide I (R = Bu₃Sn) is prepared in two steps by lithiation of propargyl Me ether, addition of the acetylide to 3-benzyl-2-benzooxazolidinone, and triflation of the free phenoxide followed by palladium-catalyzed regioselective addition of tributyltin hydride to the alkyne. I (R = Ph, 4-MeOC₆H₄, 3-pyridyl, 4-AcNHC₆H₄, 1-naphthyl, 2-O₂NC₆H₄, 3-Me-2-O₂NC₆H₃, 1-benzyl-7-indolinyl, 1-benzyl-3-indolyl, 2-BocNHC₆H₄, 2-BnNHC₆H₄, 1-benzyl-3,3-dimethyl-2-oxo-7-indolinyl) are prepared by chemo- and stereoselective Stille cross-coupling of butenanilide I (R = Bu₃Sn) with aryl or heteroaryl iodides in the presence of Pd₂(dba)₃^.CHCl₃, tri(2-furyl)phosphine, and copper (I) iodide. Catalytic asym. Heck cyclization of I (R = Ph, 4-MeOC₆H₄, 3-pyridyl, 4-AcNHC₆H₄, 1-naphthyl, 2-O₂NC₆H₄, 3-Me-2-O₂NC₆H₃, 1-benzyl-7-indolinyl, 1-benzyl-3-indolyl, 2-BocNHC₆H₄, 2-BnNHC₆H₄, 1-benzyl-3,3-dimethyl-2-oxo-7-indolinyl) in the presence of palladium (II) acetate and either (R)-BINAP or (R)-p-tol-BINAP yields arylindolines such as II containing diaryl-substituted all-carbon quaternary carbon centers in 14-95% yields and in 71-98% ee. Indolinones possessing a wide variety of aryl and heteroaryl substituents, including ones of considerable steric bulk, are prepared by this method. Heck cyclization of precursors with aryl substituents containing ortho nitro or basic amine functionalities or the bulky N-alkyl-7-oxindolyl group is sluggish or does not occur. Heck cyclizations with dimethyloxindolyl-substituted Heck precursors give both oxindoles and quinolinones; for the 1,3,3-trimethyloxindolyl-substituted compound, the replacement of 1,2,2,6,6-pentamethylpiperidine with 1,8-dimethylaminonaphthalene (Proton Sponge) increases the regioselectivity of Heck cyclization for the desired oxindole over quinolone byproducts while the corresponding 1-benzyl-3,3-dimethyloxindolyl-substituted compound undergoes cyclization mainly to quinolinone byproducts under the same conditions. Heck cyclization of a butenanilide containing an N-acetyl-N-benzylaminophenyl group yields stereoisomers derived from hindered rotation of the aryl-nitrogen bond; the atropisomers are formed directly from substrate as they interconvert very slowly under the reaction conditions. The rotational barrier between the atropisomers is determined by variable temperature NMR methods. Both atropisomers possess the same absolute stereochem. at their quaternary carbon centers. The asym. Heck reaction has potential use in the preparation of polycyclic indole alkaloids such as psycholeine and quadrigemine C. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Reference of 77876-39-2).

(2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2) belongs to chiral phosphine ligands. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.Reference of 77876-39-2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Solid-phase synthesis of recyclable diphosphine ligands was written by Heutz, Frank J. L.;Samuels, Michiel C.;Kamer, Paul C. J.. And the article was included in Catalysis Science & Technology in 2015.Safety of (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) This article mentions the following:

An efficient solid-phase synthetic approach towards diphosphine ligands is demonstrated. This modular method offers facile access to this important class of ligands, in quant. yield, providing huge potential for ligand fine-tuning. These supported ligands can be efficiently applied in asym. catalysis. Moreover, the immobilized catalysts can successfully be recycled multiple times addressing several synthetic and work-up challenges in the field of catalytic chem. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Safety of (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine)).

(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. Trivalent phosphorus compounds called phosphines have a tetrahedral electron-group geometry which makes them structurally analogous to amines.Safety of (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine)

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Synthesis of bornene-2,2′-diamino-1,1′-binaphthalene conjugates in palladium-catalysed aminocarbonylations was written by Mikle, Gabor;Boros, Borbala;Kollar, Laszlo. And the article was included in Tetrahedron: Asymmetry in 2016.Product Details of 77876-39-2 This article mentions the following:

Palladium-catalyzed aminocarbonylation of a terpenoic iodoalkene (2-iodobornene) model compound with both enantiomerically pure and racemic 2,2′-diamino-1,1′-binaphthalene (BINAM) as the N-nucleophile was carried out. All of the diastereoisomers of the monocarboxamide (N-bornenyl carboxamide) and dicarboxamide (N,N’-dinorbornenylcarboxamide) derivatives were synthesized. The diastereoselectivities of the aminocarbonylation were investigated in both cases: either racemic BINAM was used as the N-nucleophile in the aminocarbonylation of enantiomerically pure 2-iodobornene or racemic iodobornene was aminocarbonylated with enantiomerically pure BINAM with moderate diastereoselectivities. In this way, all possible diastereoisomers of binaphthalene-bornene conjugates were synthesized in moderate to high yields by asym. (diastereoselective) aminocarbonylation. 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. Thousands of arylphosphines have been used as chiral ligands for metal-catalyzed asymmetric reactions. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.Product Details of 77876-39-2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Copper-Catalyzed Asymmetric Hydroboration of 1,1-Disubstituted Alkenes was written by Wang, Zining;He, Xiaxia;Zhang, Rui;Zhang, Ge;Xu, Guoxing;Zhang, Qian;Xiong, Tao;Zhang, Qian. And the article was included in Organic Letters in 2017.Category: chiral-phosphine-ligands This article mentions the following:

A mild and efficient approach for highly regio- and enantioselective copper-catalyzed hydroboration of 1,1-diaryl substituted alkenes with bis(pinacolato)diboron (B₂Pin₂) was developed for the first time, providing facile access to a series of valuable β,β-diaryl substituted boronic esters with high enantiomeric purity. Moreover, this approach could also be suitable for hydroboration of α-alkyl styrenes for the synthesis of enantioenriched β,β-arylalkyl substituted boronic esters. Gram-scale reaction, stereospecific derivatizations, and the application of important antimuscarinic drug (R)-tolterodine for concise enantioselective synthesis further highlighted the attractiveness of this new approach. 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. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Indeed, very little research on chiral tertiary phosphine-catalyzed asymmetric reactions occurred prior to the year 2000.Category: chiral-phosphine-ligands

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

First examples of enantioselective palladium-catalyzed thiocarbonylation of prochiral 1,3-conjugated dienes with thiols and carbon monoxide: efficient synthesis of optically active β,γ-unsaturated thiol esters was written by Xiao, Wen-Jing;Alper, Howard. And the article was included in Journal of Organic Chemistry in 2001.Electric Literature of C29H30P2 This article mentions the following:

A catalyst system based on [Pd(OAc)₂]/(R,R)-DIOP has been found to effect asym. thiocarbonylation of certain prochiral 1,3-dienes to produce good yields of optically enriched β,γ-unsaturated thiol esters. The reaction was performed under an atm. of carbon monoxide (400 psi) at 110°C in methylene chloride for 60 h. The asym. thiocarbonylation proceeded with good to excellent enantioselectivities (up to 89% ee). The stereoselectivity is strongly influenced by the structure of the chiral phosphine ligands and substrates, as well as by the reaction conditions. The enantiodetn. step is assumed to be CO insertion to a π-allylpalladium intermediate. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Electric Literature of C29H30P2).

(2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2) belongs to chiral phosphine ligands. Thousands of arylphosphines have been used as chiral ligands for metal-catalyzed asymmetric reactions. Asymmetric catalytic performance is determined not only by the metal center but also by the chiral ligand selected.Electric Literature of C29H30P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis