Month: February 2023

Cyclic 1,2-Diketones as Core Building Blocks: A Strategy for the Total Synthesis of (-)-Terpestacin was written by Trost, Barry M.;Dong, Guangbin;Vance, Jennifer A.. And the article was included in Chemistry – A European Journal in 2010.Computed Properties of C52H44N2O2P2 This article mentions the following:

The sesterterpene (-)-terpestacin I is prepared using the stereoselective and enantioselective O-alkylation of diosphenols with allylic epoxides in the presence of a nonracemic diphosphine palladium catalyst and the subsequent stereoselective Claisen rearrangement to a nonracemic diosphenol with a quaternary stereocenter as the key steps. For example, reaction of 2-hydroxy-3-methyl-2-cyclopenten-1-one with 2-vinyl-2-methyloxirane (isoprene oxide) in the presence of tris(dibenzylideneacetone)dipalladium chloroform solvate and nonracemic Trost ligand II and tetrabutylammonium chloride followed by silylation yields the nonracemic tertiary allylic enol ether III (TIPS = triisopropylsilyl) in 93-95% yield and 88-96% ee; thermal rearrangement of III in chloroform (with adventitious HCl presumably as a catalyst) yields the substituted nonracemic diosphenol IV in 82-93% yield with 4-5:1 E:Z stereoselectivity. The palladium-catalyzed asym. allylic alkylation reaction of an allylic carbonate is used to generate the pendant hydroxypropyl moiety of I. Using this methodol., I is prepared in 20 steps (longest linear sequence) from com. available 2-hydroxy-3-methyl-2-cyclopenten-1-one. In the experiment, the researchers used many compounds, for example, N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4Computed Properties of C52H44N2O2P2).

N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4) belongs to chiral phosphine ligands. Generally, the efficiency of nucleophilic phosphine catalysis often depends on the nature of the tertiary phosphine. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Computed Properties of C52H44N2O2P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Palladium-Catalyzed Enantioselective C-H Arylation for the Synthesis of P-Stereogenic Compounds was written by Lin, Zi-Qi;Wang, Wei-Zhen;Yan, Shao-Bai;Duan, Wei-Liang. And the article was included in Angewandte Chemie, International Edition in 2015.Reference of 134484-36-9 This article mentions the following:

A palladium-catalyzed enantioselective C-H arylation of N-(o-bromoaryl)-diarylphosphinic amides is described for the synthesis of phosphorus compounds bearing a P-stereogenic center. The method provides good enantioselectivities and high yields. The products were readily transformed into P-chiral biphenyl monophosphine ligands. In the experiment, the researchers used many compounds, for example, (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9Reference of 134484-36-9).

(S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9) 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.Reference of 134484-36-9

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Asymmetric cross-coupling reactions: enantioselective synthesis of alkenyl sulfides was written by Cardellicchio, Cosimo;Fiandanese, Vito;Naso, Francesco. And the article was included in Gazzetta Chimica Italiana in 1991.COA of Formula: C26H28FeNP This article mentions the following:

An enantioselective synthesis of alkenyl sulfides by cross-coupling reactions between (E)- or (Z)-ArSCH:CHBr (I; Ar = Ph, 2-naphthyl, 2-pyridyl) and Grignard or organozinc reagents, using chiral complexes as catalysts, is described. The process is sensitive to several factors, e.g., the nature of the substrate, the organometallic reagent, the ligand, and the metal complex used as catalyst. Optical purities of up to 57% were achieved. The resulting unsaturated thioethers have been transformed into optically active 1-alkyl-2-phenylethenes or MeCHPhCO₂H. A new method for the synthesis of the starting (Z)-I is also reported. In the experiment, the researchers used many compounds, for example, (R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine (cas: 55700-44-2COA of Formula: C26H28FeNP).

(R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine (cas: 55700-44-2) 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.COA of Formula: C26H28FeNP

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Catalytic Asymmetric C-H Arylation of (η⁶-Arene)Chromium Complexes: Facile Access to Planar-Chiral Phosphines was written by Batuecas, Maria;Luo, Junfei;Gergelitsova, Ivana;Kramer, Katrina;Whitaker, Daniel;Vitorica-Yrezabal, Inigo J.;Larrosa, Igor. And the article was included in ACS Catalysis in 2019.Formula: C33H25OP This article mentions the following:

A catalytic asym. direct C-H arylation of (η⁶-arene)chromium complexes to obtain planar-chiral compounds is reported. The use of the hemilabile ligand H₈-BINAP(O) is key to providing high enantioselectivity in this transformation. We show that this methodol. opens the door to the synthesis of a variety of planar-chiral chromium derivatives which can be easily transformed into planar chiral mono- or diphosphines. Mechanistic studies, including synthesis and characterization of Pd and Ag complexes and their detection in the reaction mixture, suggest a Pd-catalyzed/Ag-promoted catalytic system where Ag carries out the C-H activation step. In the experiment, the researchers used many compounds, for example, (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9Formula: C33H25OP).

(S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9) belongs to chiral phosphine ligands. Generally, the efficiency of nucleophilic phosphine catalysis often depends on the nature of the tertiary phosphine. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.Formula: C33H25OP

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Highly Regioselective and Helix-Sense Selective Living Polymerization of Phenyl and Alkoxyallene Using Chiral Nickel(II) Catalysts was written by Zhou, Li;Li, Chong-Long;Gao, Run-Tan;Kang, Shu-Ming;Xu, Lei;Xu, Xun-Hui;Liu, Na;Wu, Zong-Quan. And the article was included in Macromolecules (Washington, DC, United States) in 2021.Recommanded Product: (R)-N-((S)-2-(Diphenylphosphanyl)-1-phenylethyl)-2-methylpropane-2-sulfinamide This article mentions the following:

Facile synthesis of high optically active helical polymers from achiral monomers still remains a great challenge. In this work, two chiral Ni(II) catalysts bearing chiral R- or S-2a ligands were facilely prepared which can efficiently initiate the living/controlled polymerization of allene monomers and afford well-defined polyallenes in high yields with controlled mol. masses (M_ns) and low mol. mass distributions (M_w/M_ns). The catalysts showed interesting regioselectivity on the cumulated double bonds of allene monomers, as the polymerizations were highly selective which occurred on 2,3-double bonds. Moreover, the polymerization of achiral allene monomers using chiral Ni(II) catalysts showed remarkable helix-sense selectivity. The yielded polyallenes exhibited high optical activity due to the formation of a predominant one-handed helix as revealed by CD, UV-vis, and direct at. force microscopy (AFM) observations as well. The predominant one-handed helicity of the generated polyallenes was solely determined by the chirality of the Ni(II) catalysts. In the experiment, the researchers used many compounds, for example, (R)-N-((S)-2-(Diphenylphosphanyl)-1-phenylethyl)-2-methylpropane-2-sulfinamide (cas: 1803239-44-2Recommanded Product: (R)-N-((S)-2-(Diphenylphosphanyl)-1-phenylethyl)-2-methylpropane-2-sulfinamide).

(R)-N-((S)-2-(Diphenylphosphanyl)-1-phenylethyl)-2-methylpropane-2-sulfinamide (cas: 1803239-44-2) 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: (R)-N-((S)-2-(Diphenylphosphanyl)-1-phenylethyl)-2-methylpropane-2-sulfinamide

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Highly enantioselective spirocyclization of 1,6-enynes catalyzed by cationic skewphos rhodium(I) complex was written by Mikami, Koichi;Yusa, Yukinori;Hatano, Manabu;Wakabayashi, Kazuki;Aikawa, Kohsuke. And the article was included in Chemical Communications (Cambridge, United Kingdom) in 2004.Computed Properties of C29H30P2 This article mentions the following:

A cationic rhodium(I) complex having a skewphos ligand was a highly enantioselective catalyst for asym. carbocyclization of 1,6-enynes. 1,6-Enynes, e.g., I, underwent spirocyclization to give spiro-cycles, e.g., II, with good control of the newly formed quaternary stereogenic centers of the spiro-rings. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Computed Properties of C29H30P2).

(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. Trivalent phosphorus compounds called phosphines have a tetrahedral electron-group geometry which makes them structurally analogous to amines.Computed Properties of C29H30P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Geminal Dicarboxylates as Carbonyl Surrogates for Asymmetric Synthesis. Part I. Asymmetric Addition of Malonate Nucleophiles was written by Trost, Barry M.;Lee, Chul Bom. And the article was included in Journal of the American Chemical Society in 2001.HPLC of Formula: 174810-09-4 This article mentions the following:

Asym. alkylations of allylic geminal dicarboxylates with dialkyl malonates have been investigated. The requisite allylic geminal dicarboxylates are prepared in good yields and high isomeric purities either by ferric chloride-catalyzed addition of acid anhydrides to α,β-unsaturated aldehydes or by palladium-catalyzed isomerization and addition reactions of propargylic acetates with acetic acid. E.g., treatment of trans-cinnamaldehyde with 5 equivalent in the presence of 0.5% iron (III) chloride gave (E)-PhCH:CHCH(OAc)₂ in 85% yield. E.g., treatment of (S)-MeCH[OSi(Ph)₂CMe₃]CCCH₂OAc with 1.2 equivalent acetic acid and 1 mol% tetrakis(triphenylphosphine)palladium in toluene at 110° gave (E,S)-MeCH[OSi(Ph)₂CMe₃]CH:CCHCH(OAc)₂ in 81% yield. The complex of di(allylchloropalladium) and nonracemic ligands derived from di(2-diphenylphosphinobenzoyl) amides of trans-1,2-diaminocyclohexane most efficiently catalyzed the asym. process to provide allylic carboxylate esters with high ee. E.g., sodium hydride was added to a solution of di-Me 2-methylmalonate and the mixture stirred at ambient temperature until gas evolution ceased; di(allylpalladium chloride), the (R,R)-trans-1,2-diaminocyclohexane di(2-diphenylphosphinobenzoyl) amide, and (E)-PhCH:CHCH(OAc)₂ were added and the mixture was stirred for 2 h to give (R,E)-PhCH:CHCH(OAc)C(Me)(CO₂Me)₂ in 92% yield as a single regioisomer in >95% ee. By systematic optimization studies, factors affecting the enantioselectivity of the reaction have been probed. In general, higher ee’s have been achieved with those conditions which facilitate kinetic capture of the incipient π-allylpalladium intermediate. These conditions also proved effective for achieving high regioselectivities. The minor regioisomeric product was formed when reactive substrates or achiral ligands were employed for the reaction, and could be minimized through the use of the chiral ligand. Under the established conditions, the alkylation of various gem-dicarboxylates afforded monoalkylated products in high yields with greater than 90% ee. The process constitutes the equivalent of an addition of a stabilized nucleophile to a carbonyl group with high asym. induction. 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. 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.HPLC of Formula: 174810-09-4

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Synthesis, Characterization, and Reactivity of Hydroxycyclopentadienyl Cobalt Complexes was written by Wu, Weiwei;Solis-Ibarra, Diego;Walker, Katherine L.;Waymouth, Robert M.. And the article was included in Organometallics in 2018.Product Details of 77876-39-2 This article mentions the following:

The reaction of tetraphenylcyclopentadienone with Co₂(CO)₈ generates the mixed-valence tricobalt complex [[Ph₄C₄CO]Co(CO)₂]₂[μ-Co(MeCN)₂]. In contrast to the conventional Pauson-Khand reaction to generate cyclopentadienone ligated Co complexes, this method benefits from both mild reaction conditions and high yields. Treatment of this tricobalt complex with proton sources such as H₂O or alcs. yields the monomeric hydroxy-tetraphenylcyclopentadienyl Co complex [Ph₄CpOH]Co(CO)₂. Phosphite substituted monomeric Co complexes [Ph₄CpOH]Co(CO)[P(OR)₃] were also synthesized, and protonation of these complexes transiently formed Co hydride species. 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. Generally, the efficiency of nucleophilic phosphine catalysis often depends on the nature of the tertiary phosphine. 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

High-Throughput Ligand Screening Enables the Enantioselective Conjugate Borylation of Cyclobutenones to Access Synthetically Versatile Tertiary Cyclobutylboronates was written by Clement, Helen A.;Boghi, Michele;McDonald, Rory M.;Bernier, Louise;Coe, Jotham W.;Farrell, William;Helal, Christopher J.;Reese, Matthew R.;Sach, Neal W.;Lee, Jack C.;Hall, Dennis G.. And the article was included in Angewandte Chemie, International Edition in 2019.Recommanded Product: 77876-39-2 This article mentions the following:

Cyclobutane rings are important in medicinal chem., yet few enantioselective methods exist to access this scaffold. In particular, cyclobutylboronates are receiving increasing attention in the literature due to the synthetic versatility of alkylboronic esters and the increasing role of boronic acids in drug discovery. Herein, a conjugate borylation of α-alkyl,β-aryl/alkyl cyclobutenones is reported leading to the first synthesis of enantioenriched tertiary cyclobutylboronates. Cyclobutanones with two stereogenic centers are obtained in good to high yield, with high enantioselectivity and diastereoselectivity. Vital to this advance are the development of a novel approach to α,β unsym. disubstituted cyclobutenone substrates and the use of a high-throughput chiral ligand screening platform. The synthetic utility of both the boronic ester and ketone functionalities is displayed, with remarkable chemoselectivity for either group being possible in this small ring scaffold. In the experiment, the researchers used many compounds, for example, (2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2Recommanded Product: 77876-39-2).

(2S,4S)-Pentane-2,4-diylbis(diphenylphosphine) (cas: 77876-39-2) belongs to chiral phosphine ligands. Generally, the efficiency of nucleophilic phosphine catalysis often depends on the nature of the tertiary phosphine. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.Recommanded Product: 77876-39-2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Asymmetric Catalytic Hydrogenolysis of Aryl-Halide Bonds in Fused Arene Chromium and Ruthenium Complexes was written by Mercier, Audrey;Urbaneja, Xavier;Yeo, Wee Chuan;Chaudhuri, Piyali Datta;Cumming, Graham R.;House, David;Bernardinelli, Gerald;Kuendig, E. Peter. And the article was included in Chemistry – A European Journal in 2010.Formula: C26H28FeNP This article mentions the following:

Access to highly enantioenriched planar chiral [Cr(5-bromonaphthalene)(CO)₃] (6), [Ru(η⁵-C₅R₅)(5-bromonaphthalene)][PF₆] (42) and [Ru(η⁵-C₅R₅)(4-bromoindene)] (44) was sought using asym. hydrogenolysis of [Cr(5,8-dibromonaphthalene)(CO)₃] (5), [Ru(η⁵-C₅R₅)(5,8-dibromonaphthalene)] (39) and [Ru(η⁵-C₅R₅)(4,7-dibromoindene)] (40), resp. Initial efforts focused on the chromium complex 5. Pd⁰ catalysts with dimethoxyethane as the solvent and LiBH₄ or NaBH₃CN as a hydride source worked best. Nineteen chiral bidentate phosphorus ligands were screened in this reaction. Asym. induction was low to modest with product ee’s in the range of 4 to 52 % and yields of 6 of up to 70 %. Chiral phosphoramidite ligands proved superior and a bulky ligand derived from a Whitesell amine and 3,3′-diphenyl-binaphthol afforded 6 with an ee of 97%. The high enantioselectivity is largely due to the initial desymmetrization reaction though kinetic resolution also plays an important role as shown by the determination of a selectivity factor s = 8.5 at -10°. Initially high ligand loadings (4 equivalent/Pd) were necessary to achieve good asym. induction. This could be traced to the trapping of the chiral ligand by borane formed in the reaction. Addition of 1,4-diazabicyclo[2.2.2]octane (DABCO) suppressed this, and its addition led to the use of Pd and chiral ligand in a 1:1.2 ratio. Asym. hydrogenolysis of cationic dibromonaphthalene and neutral dibromoindenyl complexes of Ru cyclopentadienyl complexes was investigated and afforded the following results: [RuCp(5-bromonaphthalene)][PF₆] (39a; 75%, 90% ee), [RuCp*(5-bromonaphthalene)][PF₆] (39b; 88%, 99% ee), [RuCp(4-bromoindenyl)] (44a; 72%, 96% ee), and [RuCp*(4-bromoindenyl)] (44b; 62%, 68% ee). 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. Trivalent phosphorus compounds called phosphines have a tetrahedral electron-group geometry which makes them structurally analogous to amines.Formula: C26H28FeNP

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis