Day: February 22, 2023

A new practical asymmetric synthesis of C₂-symmetrical 1,1′-ferrocenyl diols via CBS-reduction was written by Schwink, Lothar;Knochel, Paul. And the article was included in Tetrahedron Letters in 1996.Name: (R,R)-2,2′-Bis[(R)-(N,N-dimethylamino)(phenyl)methyl]-1,1′-bis(diphenylphosphino)ferrocene This article mentions the following:

Oxazaborolidine-catalyzed borane-reduction of ferrocenyl diketones I [R = Me, i-Pr, pentyl, Ph, (CH₂)₃CO₂Me] provides C₂-sym. ferrocenyl diols (R,R)-1 (II) in >98% ee accompanied by small amounts of the meso-diols (R,S)-1. The utility of 1 for the preparation of various potential ligands for asym. catalysis such as III (R = Ph, pentyl) is demonstrated. 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: 174467-31-3Name: (R,R)-2,2′-Bis[(R)-(N,N-dimethylamino)(phenyl)methyl]-1,1′-bis(diphenylphosphino)ferrocene).

(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. Although many reactions require more nucleophilic trialkylphosphines as catalysts, only a few chiral trialkylphosphines are available. Asymmetric catalytic performance is determined not only by the metal center but also by the chiral ligand selected.Name: (R,R)-2,2′-Bis[(R)-(N,N-dimethylamino)(phenyl)methyl]-1,1′-bis(diphenylphosphino)ferrocene

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Catalytic Asymmetric Synthesis of α-Quaternary Proline Derivatives by 1,3-Dipolar Cycloaddition of α-Silylimines was written by Hernandez-Toribio, Jorge;Padilla, Silvia;Adrio, Javier;Carretero, Juan C.. And the article was included in Angewandte Chemie, International Edition in 2012.Application of 133545-16-1 This article mentions the following:

We report an efficient asym. protocol for the Cu^I-catalyzed 1,3-dipolar cycloaddition of α-silylimines to activated olefins. A variety of α-quaternary proline derivatives were obtained with good yields and excellent levels of diastereoselectivity and enantiocontrol with a variety of dipolarophiles, such as maleimides and α,β-unsaturated sulfones (up to 99% ee). The use of the bulky DTBM-Segphos ligand proved to be crucial for attaining this high enantioselectivity. 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. 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.Application of 133545-16-1

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Hidden Enantioselective Hydrogenation of N-Silyl Enamines and Silyl Enol Ethers in Net C:N and C:O Hydrosilylations Catalyzed by Ru-S Complexes with One Monodentate Chiral Phosphine Ligand was written by Baehr, Susanne;Oestreich, Martin. And the article was included in Organometallics in 2017.SDS of cas: 134484-36-9 This article mentions the following:

Ruthenium thiolate complexes with one chiral monodentate phosphine ligand are applied to enantioselective hydrosilylation of enolizable imines and ketones. The structural features of the catalyst exclude the presence of more than one phosphine ligand at the ruthenium center in the enantioselectivity-determining step. The enantiomeric excesses obtained in these reduction reactions are moderate (up to 66% ee), but the stereochem. outcome enables an exptl. anal. of the reaction pathways operative in this catalysis. A two-step sequence consisting of successive N-Si/O-Si dehydrogenative coupling and enamine/enol ether hydrogenation is the prevailing mechanism of action. Both steps involve cooperative bond activation at the Ru-S bond of the coordinatively unsaturated ruthenium complex: Si-H bond activation in the dehydrogenative coupling and heterolytic H-H splitting in the hydrogenation. Previously documented side reactions such as deprotonation/protonation equilibrium as well as competing direct C:N or C:O hydrogenation have been excluded. In the experiment, the researchers used many compounds, for example, (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9SDS of cas: 134484-36-9).

(S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9) 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. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.SDS of cas: 134484-36-9

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Towards asymmetric Au-catalyzed hydroxy- and alkoxycyclization of 1,6-enynes was written by Chao, Chung-Meng;Genin, Emilie;Toullec, Patrick Y.;Genet, Jean-Pierre;Michelet, Veronique. And the article was included in Journal of Organometallic Chemistry in 2009.Recommanded Product: 352655-61-9 This article mentions the following:

The efficiency of a Au(III)/chiral ligand system has been studied. The association of several chiral mono- and bidentate phosphanes with gold has been tested in the formal addition of an oxygen nucleophile to an alkene followed by a cyclization process, namely the hydroxycyclization reaction of 1,6-enynes. The use of (R)-4-MeO-3,5-(t-Bu)₂-MeOBIPHEP ligand led to clean cycloisomerizations and afforded the highest enantiomeric excesses. The enantiomeric excesses were highly dependant on the substrate/nucleophile combination. A ³¹P NMR study of the catalytic species tends to prove that Au(III) catalyst may be reduced to Au(I) intermediate in the presence of phosphanes. 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. 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. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.Recommanded Product: 352655-61-9

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Enantioselective C-C Bond Cleavage Creating Chiral Quaternary Carbon Centers was written by Matsuda, Takanori;Shigeno, Masanori;Makino, Masaomi;Murakami, Masahiro. And the article was included in Organic Letters in 2006.Name: (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) This article mentions the following:

A chiral all-carbon benzylic quaternary carbon center was created by the asym. intramol. addition/ring-opening reaction of a boryl-substituted cyclobutanone, which involved enantioselective β-carbon elimination from a sym. rhodium cyclobutanolate. The asym. reaction was successfully applied to a synthesis of sesquiterpene, (-)-α-herbertenol (I). In the experiment, the researchers used many compounds, for example, (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) (cas: 133545-16-1Name: (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine)).

(R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) (cas: 133545-16-1) belongs to chiral phosphine ligands. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Name: (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine)

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

The total synthesis of (-)-strempeliopine via palladium-catalyzed decarboxylative asymmetric allylic alkylation was written by An, Yi;Wu, Mengjuan;Li, Weijian;Li, Yaling;Wang, Zhenzhen;Xue, Yansong;Tang, Pei;Chen, Fener. And the article was included in Chemical Communications (Cambridge, United Kingdom) in 2022.Electric Literature of C28H23F9NOP This article mentions the following:

In the work reported herein, the concise and enantioselective total synthesis of the Schizozygine alkaloid (-)-strempeliopine was developed. This synthetic strategy featured the palladium-catalyzed decarboxylative asym. allylic alkylation of N-benzoyl lactam to set up the absolute configuration at the C20 position, a highly diastereoselective one-pot Bischler-Napieralski/lactamization and iminium reduction sequence for the construction of the pentacyclic core structure, and the late-stage dearomative addition of indole, leading to the otherwise difficult-to-achieve hexacyclic indoline framework with complete control of four neighboring stereocenters. In the experiment, the researchers used many compounds, for example, (R)-2-(2-(Bis(4-(trifluoromethyl)phenyl)phosphino)-5-(trifluoromethyl)phenyl)-4-(tert-butyl)-4,5-dihydrooxazole (cas: 1006708-91-3Electric Literature of C28H23F9NOP).

(R)-2-(2-(Bis(4-(trifluoromethyl)phenyl)phosphino)-5-(trifluoromethyl)phenyl)-4-(tert-butyl)-4,5-dihydrooxazole (cas: 1006708-91-3) 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. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.Electric Literature of C28H23F9NOP

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Catalytic asymmetric cyclocarbonylation of o-isopropenylphenols: Enantioselective synthesis of six-membered ring lactones was written by Dong, Chune;Alper, Howard. And the article was included in Journal of Organic Chemistry in 2004.Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) This article mentions the following:

Cyclocarbonylation of o-isopropenylphenols with CO and H₂, using Pd(OAc)₂ and (+)-DIOP as the chiral catalyst, in CH₂Cl₂ afforded 3,4-dihydro-4-methylcoumarins, e.g., I, in good yields and enantiomeric excess. The stereoselectivity was influenced by the structure of the chiral phosphine ligands and substrates, as well as by the reaction conditions. 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. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine)

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

²H-quadrupolar coupling-based analysis of stereochemical and regiochemical memory in the Pd-catalyzed allylic alkylation of iso-cinnamyl type substrates employing the chiral monophosphine ligands “MOP” and “MAP” was written by Gouriou, Laure;Lloyd-Jones, Guy C.;Vyskocil, Stepan;Kocovsky, Pavel. And the article was included in Journal of Organometallic Chemistry in 2003.Safety of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine This article mentions the following:

The reaction of isocinnamyl acetate with NaC(Me)(CO₂Me)₂, catalyzed by Pd-MOP (MOP = 2-methoxy-2′-diphenylphosphino-1,1′-binaphthalene) is known to proceed with a regiochem. memory effect that results in the predominant generation of the branched alkylation product. The analogous reaction employing MAP as ligand (MAP = 2-N,N-dimethylamino-2′-diphenylphosphino-1,1′-binaphthalene) proceeds with normal regioselectivity to generate predominantly the linear isomer of product. A ²H-NMR based anal., employing quadrupolar coupling in a chiral liquid crystal matrix, has been developed to facilitate the simultaneous study of the regiochem. and stereochem. outcome of the reaction of both enantiomers of iso-cinnamyl ester substrates in ²H-labeled but racemic samples. The anal. allows the comparison of relative rates of two competing isomerization processes occurring in the π-allyl intermediates in the Pd-catalyzed reaction, one of which facilitates asym. induction, the other resulting in loss of regiochem. memory. It is demonstrated that the two processes are partially coupled and that this then limits the attainment of high global enantiomeric excess in the branched product to reactions that proceed with low regiochem. retention. A key factor for the observation of high regiochem. memory is found to be the nucleophilicity of the malonate anion and the electrophilicity of the Pd-π-allyl intermediate with reduction in the reactivity of either partner resulting in the onset of substantial loss of memory. In the experiment, the researchers used many compounds, for example, (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9Safety 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. At present, the synthesis of new chiral phosphines designed specifically for nucleophilic organocatalysis remains a significant challenge. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.Safety of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Palladium-Catalyzed Asymmetric Intramolecular Reductive Heck Desymmetrization of Cyclopentenes: Access to Chiral Bicyclo[3.2.1]octanes was written by Yuan, Zhenbo;Feng, Ziwen;Zeng, Yuye;Zhao, Xiaobin;Lin, Aijun;Yao, Hequan. And the article was included in Angewandte Chemie, International Edition in 2019.Safety of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine This article mentions the following:

A palladium-catalyzed asym. reductive Heck reaction of unactivated aliphatic alkenes, with eliminable β-hydrogen atoms, was realized for the first time. A series of optically active bicyclo[3.2.1]octanes bearing chiral quaternary and tertiary carbon stereocenters were obtained in good yields with excellent enantioselectivities, exhibited good functional-group tolerance and scalability. Moreover, deuterated optically active bicyclo[3.2.1]octanes were also obtained in high efficiency. In the experiment, the researchers used many compounds, for example, (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine (cas: 134484-36-9Safety 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. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Safety of (S)-(2′-Methoxy-[1,1′-binaphthalen]-2-yl)diphenylphosphine

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Highly Chemoselective Metal-Free Reduction of Phosphine Oxides to Phosphines was written by Li, Yuehui;Lu, Liang-Qiu;Das, Shoubhik;Pisiewicz, Sabine;Junge, Kathrin;Beller, Matthias. And the article was included in Journal of the American Chemical Society in 2012.Reference of 37002-48-5 This article mentions the following:

Unprecedented chemoselective reductions of phosphine oxides to phosphines proceed smoothly in the presence of catalytic amounts of specific Bronsted acids. By utilizing inexpensive silanes, e.g., PMHS or (EtO)₂MeSiH, other reducible functional groups such as ketones, aldehydes, olefins, nitriles, and esters are well-tolerated under optimized conditions. 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: 37002-48-5Reference of 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. At present, the synthesis of new chiral phosphines designed specifically for nucleophilic organocatalysis remains a significant challenge. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.Reference of 37002-48-5

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis