Day: February 22, 2023

exo-Selective construction of spiro-[butyrolactone-pyrrolidine] via 1,3-dipolar cycloaddition of azomethine ylides with α-methylene-γ-butyrolactone catalyzed by Cu(I)/DTBM-BIPHEP was written by Li, Qing-Hua;Liu, Tang-Lin;Wei, Liang;Zhou, Xiang;Tao, Hai-Yan;Wang, Chun-Jiang. And the article was included in Chemical Communications (Cambridge, United Kingdom) in 2013.Recommanded Product: 352655-61-9 This article mentions the following:

An expedient access to optically active spiro-[butyrolactone-pyrrolidine] was successfully developed via an unprecedented Cu(I)-catalyzed exo-selective 1,3-DC of azomethine ylides with α-methylene-γ-butyrolactone, which exhibited high diastereoselectivity (>98 : 2), excellent enantioselectivity (96->99% ee) and a broad substrate scope under mild conditions [e.g., N-(4-chlorobenzylidene)glycine Me ester + α-methylene-γ-butyrolactone in presence of Cu(I)/DTBM-BIPHEP afforded I in >98:2 diastereoselectivity and almost perfect enantioselectivity]. 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: 352655-61-9Recommanded Product: 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. Although many reactions require more nucleophilic trialkylphosphines as catalysts, only a few chiral trialkylphosphines are available. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.Recommanded Product: 352655-61-9

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Ligand Tuning in Asymmetric Catalysis: Mono- and Bis-Phospholanes for a Prototypical Pd-Catalyzed Asymmetric Allylation Reaction was written by Yan, Yuan-Yong;RajanBabu, T. V.. And the article was included in Organic Letters in 2000.Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) This article mentions the following:

Enantioselectivities and yields comparable to the best catalysts reported previously can be achieved in the addition of potassium di-Me malonate to diphenylallyl acetate by the use of Pd(0) complexes of bis-phospholanes prepared from D-mannitol. By appropriate changes in the C(2)-C(5) substituents, rare example of a useful monophosphine can also be prepared by a similar route. In both instances, chirality of C(3) and C(5) oxygen seems to play a crucial role in the asym. induction. 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: 37002-48-5Name: (((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. 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.Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine)

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Enantioselective imine hydrogenation with Ir diphosphine catalysts: fighting deactivation was written by Blaser, Hans-Ulrich;Pugin, Benoit;Spindler, Felix;Togni, Antonio. And the article was included in Comptes Rendus Chimie in 2002.Quality Control of (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) This article mentions the following:

While Ir diphosphine complexes are very active catalysts for the enantioselective hydrogenation of imines with good to excellent enantioselectivity, their deactivation is often a serious problem, leading to low catalyst productivity. Our study describes attempts to stabilize Ir catalysts with DIOP, BDPP and BPPM ligands for the hydrogenation of different imines. The best results were obtained with complexes immobilized on silica gel and with bimetallic W-Ir and Mo-Ir complexes. In most cases, enantiomeric excesses as well as initial rates were only slightly affected while the stability of the catalysts was enhanced significantly. 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. 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. Asymmetric catalytic performance is determined not only by the metal center but also by the chiral ligand selected.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

Enantioselective preparation of C₂-symmetrical ferrocenyl ligands for asymmetric catalysis was written by Schwink, Lothar;Knochel, Paul. And the article was included in Chemistry – A European Journal in 1998.Category: chiral-phosphine-ligands This article mentions the following:

Corey-Bakshi-Shibata (CBS) reduction of the 1,1′-diacylmetallocenes of Fe and Ru (e.g. 1,1′-(ClCH₂CH₂CH₂C(O))₂ferrocene) provides the C₂-sym. diols 4 (e.g. (R,R)-1,1′-(MeCH(OH))₂ferrocene) and 10, which proved to be useful starting materials for stereo-controlled ligand synthesis. Diols 4 and 10 can be easily converted to a wide range of diamines, diphosphines, and dithioacetates by nucleophilic substitution of the hydroxyl function with full retention of configuration. Also, the aminophosphines 30 (e.g. (αR,α’R)-2,2′-bis(α-(dimethylamino)(phenyl)methyl)-(S,S)-1,1′-bis(diphenylphosphino)ferrocene) and 31 (the Ru analog of the example for 30) become easily accessible. Compounds 30 and 31 were used as ligands complexed to Pd in enantioselective cross-coupling of racemic secondary Grignard reagents with vinyl bromides. A selectivity up to 93% ee could be reached for the 1st time in the preparation of (S)-(E)-1,3-diphenyl-1-butene, which was transformed into the enantiomerically pure chiral building block (2R,4R)-2,4-diphenyl-3-pentanol with a pseudoasym. center in a straightforward, three-step synthesis. In the experiment, the researchers used many compounds, for example, (R,R)-2,2′-Bis[(R)-(N,N-dimethylamino)(phenyl)methyl]-1,1′-bis(diphenylphosphino)ferrocene (cas: 174467-31-3Category: chiral-phosphine-ligands).

(R,R)-2,2′-Bis[(R)-(N,N-dimethylamino)(phenyl)methyl]-1,1′-bis(diphenylphosphino)ferrocene (cas: 174467-31-3) 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. Category: chiral-phosphine-ligands

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Immobilization of optically active rhodium-diphosphine complexes on porous silica via hydrogen bonding was written by Bianchini, Claudio;Barbaro, Pierluigi;Dal Santo, Vladimiro;Gobetto, Roberto;Meli, Andrea;Oberhauser, Werner;Psaro, Rinaldo;Vizza, Francesco. And the article was included in Advanced Synthesis & Catalysis in 2001.SDS of cas: 37002-48-5 This article mentions the following:

The authors describe, for the 1st time, the supported hydrogen-bonded (SHB) immobilization of various optically pure Rh(I) diphosphine complexes, including [((R)-(R)-BDPBzPSO₃)Rh(nbd)] (1), which contains the new chiral anionic ligand 4-((R)-Ph₂PCHMe)₂CHCH₂C₆H₄SO₃^–, [((+)-DIOP)-Rh(nbd)]OTf (2), and [((S)-BINAP)Rh(nbd)]OTf (3) (nbd = norbornadiene). A preliminary study of the potential of the resulting SHB catalysts in the enantioselective hydrogenation of prochiral olefins is also reported. 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: 37002-48-5SDS of cas: 37002-48-5).

(((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. Indeed, very little research on chiral tertiary phosphine-catalyzed asymmetric reactions occurred prior to the year 2000.SDS of cas: 37002-48-5

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Stereodivergent Synthesis of Tertiary Fluoride-Tethered Allenes via Copper and Palladium Dual Catalysis was written by Yang, Shao-Qian;Wang, Yi-Fan;Zhao, Wei-Cheng;Lin, Guo-Qiang;He, Zhi-Tao. And the article was included in Journal of the American Chemical Society in 2021.Recommanded Product: 352655-61-9 This article mentions the following:

Herein we describe a protocol for the unprecedented stereodivergent synthesis of tertiary fluoride-tethered allenes bearing a stereogenic center and stereogenic axis via Cu/Pd synergistic catalysis. A broad scope of conjugated enynes are coupled with various α-fluoroesters in high yields with high diastereoselectivities and generally >99% ee. In addition, the four stereoisomers of the allene products ensure precise access to the corresponding four stereoisomers of the fluorinated hydrofurans via a novel stereodivergent axial-to-central chirality transfer process. 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: 352655-61-9Recommanded Product: 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. Thousands of arylphosphines have been used as chiral ligands for metal-catalyzed asymmetric reactions. Effective chiral catalysts for nucleophilic phosphine catalysis are scarce, seriously limiting the development of asymmetric variants. Recommanded Product: 352655-61-9

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Palladium/PC-Phos-Catalyzed Enantioselective Arylation of General Sulfenate Anions: Scope and Synthetic Applications was written by Wang, Lei;Chen, Mingjie;Zhang, Peichao;Li, Wenbo;Zhang, Junliang. And the article was included in Journal of the American Chemical Society in 2018.Reference of 2162939-89-9 This article mentions the following:

Herein we reported an efficient palladium-catalyzed enantioselective arylation of both alkyl and aryl sulfenate anions to deliver various chiral sulfoxides I [R¹ = Bn, CH₃(CH₂)₁₁, Me, i-Pr, cyclopentyl, etc.; R² = H, 4-Me, 4-OMe, 3-CO₂Me, 3-Cl, etc.] in good yields (up to 98%) with excellent enantioselectivities (up to 99% ee) by the use of our developed chiral O,P-ligands (PC-Phos). PC-Phos are easily prepared in short steps from inexpensive com. available starting materials. The single-crystal structure of the PC4/PdCl₂ showed that a rarely observed 11-membered ring was formed via the O,P-coordination with the palladium(II) center. The salient features of this method include general substrate scope, ease of scale-up, applicable to the late-stage modification of bioactive compounds, and the synthesis of a marketed medicine Sulindac. In the experiment, the researchers used many compounds, for example, (R)-N-((S)-1-(5-(Diphenylphosphanyl) -9,9-dimethyl-9H-xanthen-4-yl)-2,2-dimethylpropyl)-2-methylpropane-2-sulfinamide (cas: 2162939-89-9Reference of 2162939-89-9).

(R)-N-((S)-1-(5-(Diphenylphosphanyl) -9,9-dimethyl-9H-xanthen-4-yl)-2,2-dimethylpropyl)-2-methylpropane-2-sulfinamide (cas: 2162939-89-9) 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.Reference of 2162939-89-9

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

The use of silyl ketene acetals and enol ethers in the catalytic enantioselective alkylative ring opening of oxa/aza bicyclic alkenes was written by Zhang, Lei;Le, Christine M.;Lautens, Mark. And the article was included in Angewandte Chemie, International Edition in 2014.Synthetic Route of C52H60FeN2P2 This article mentions the following:

Silyl ketene acetals and enol ethers are employed as reactive and functional group tolerant nucleophiles in the enantioselective rhodium-catalyzed alkylative ring opening of a diverse class of oxa/azabicyclic alkenes. This method provides access to enantio-enriched dihydronaphthalene and cyclohexene scaffolds, which have the potential to be derivatized toward core motifs of naphthoquinone and sesquiterpene natural products. In the experiment, the researchers used many compounds, for example, (R,R)-2,2′-Bis[(R)-(N,N-dimethylamino)(phenyl)methyl]-1,1′-bis(diphenylphosphino)ferrocene (cas: 174467-31-3Synthetic Route of C52H60FeN2P2).

(R,R)-2,2′-Bis[(R)-(N,N-dimethylamino)(phenyl)methyl]-1,1′-bis(diphenylphosphino)ferrocene (cas: 174467-31-3) belongs to chiral phosphine ligands. At present, the synthesis of new chiral phosphines designed specifically for nucleophilic organocatalysis remains a significant challenge. Trivalent phosphorus compounds called phosphines have a tetrahedral electron-group geometry which makes them structurally analogous to amines.Synthetic Route of C52H60FeN2P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis