Month: February 2023

Asymmetric synthesis of homoproline derivatives via Rh(I)-catalyzed hydrogenation using chiral bisphosphines as ligands was written by Zhang, Yong Jian;Park, Jung Hwan;Lee, Sang-gi. And the article was included in Tetrahedron: Asymmetry in 2004.Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine) This article mentions the following:

It has been demonstrated for the first time that Rh(I)-catalyzed asym. hydrogenation of cyclic β-enamino acid derivatives I [R¹ = Me, R² = Me (1a), OBu-t, OEt; R¹ = Et, R² = Me] using chiral bisphosphines could be a highly efficient synthetic method for optically active homoproline derivatives The enantioselectivity and conversion yield were largely dependent upon the chiral ligand. Using Me-BDPMI which forms a seven-membered metal chelate, the N-acetylated β-enamino acid Me ester 1a was hydrogenated to give optically active homoproline derivative II with 100% conversion and 96% ee. 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. 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.Name: (((4S,5S)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene))bis(diphenylphosphine)

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

Catalytic Asymmetric Synthesis of Quaternary Carbon Centers. Exploratory Investigations of Intramolecular Heck Reactions of (E)-α,β-Unsaturated 2-Haloanilides and Analogs To Form Enantioenriched Spirocyclic Products. [Erratum to document cited in CA129:161471] was written by Ashimori, Atsuyuki;Bachand, Benoit;Overman, Larry E.;Poon, Daniel J.. And the article was included in Journal of the American Chemical Society in 2000.SDS of cas: 37002-48-5 This article mentions the following:

In Table 5, the conversion associated with several table entries is ambiguous. The original version of the table, which is clearer and incorporates chem. structures for all conversions, is now available as Supporting Information: “Supporting Information Available: Table 5 showing the scope of asym. Heck cyclizations of (E)-α,β-unsaturated 2-haloanilides with Pd(R)-BINAP (PDF). This material is available free of charge via the Internet at http://pubs.acs.organic”. 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. At present, the synthesis of new chiral phosphines designed specifically for nucleophilic organocatalysis remains a significant challenge. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.SDS of cas: 37002-48-5

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

Allylic alcohols: Valuable synthetic equivalents of non-activated alkenes in gold-catalyzed enantioselective alkylation of indoles was written by Bandini, Marco;Gualandi, Andrea;Monari, Magda;Romaniello, Alessandro;Savoia, Diego;Tragni, Michele. And the article was included in Journal of Organometallic Chemistry in 2010.Safety of (R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl This article mentions the following:

The recent booming of gold catalysis has demonstrated that unprecedented transformations can be realized in a highly selective manner. Moreover, due to the growing availability of chiral organic ligands, gold-catalysis can be considered as one of most dynamic hot spots in asym. synthesis. However, in this context, the use of non-activated olefinic C-C double bonds is still largely unexplored due to the intrinsic inertness of C=C (respect to allenes and alkynes) in taking part in nucleophilic additions assisted by π-electrophilic activations. Allylic alcs. have been demonstrated to be feasible “surrogates” of non-activated alkenes for the enantioselective allylic alkylation of indoles catalyzed by chiral gold(I) complexes. In this investigation, a full account addressing efficiency and substrate scope of such a process is presented. The products, tetrahydrocarbazoles or tetrahydro-β-carbolines, are obtained in moderate to good yields and 40-86% ee from the corresponding Z-allylic alc.-containing substrates, while the E isomers are unreactive. 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: 352655-61-9Safety of (R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl).

(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. 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.Safety of (R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

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