Day: February 22, 2023

Copper-catalyzed enantioselective allylic cross-coupling with alkylboranes was written by Hojoh, Kentaro;Shido, Yoshinori;Nagao, Kazunori;Mori, Seiji;Ohmiya, Hirohisa;Sawamura, Masaya. And the article was included in Tetrahedron in 2015.Name: (R)-(-)-2,2′-Bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-6,6′-dimethoxy-1,1′-biphenyl This article mentions the following:

Nonracemic alkenes such as (S)-3,4-(MeO)₂C₆H₃(CH₂)₃CH(CH₂CH₂Ph)CH:CH₂ and allylic silanes such as (S)-Me(CH₂)₇CH(SiMe₂Ph)CH:CH₂ were prepared by enantioselective S_N2′-type allylic substitution reactions of (Z)-allylic chlorides such as (Z)-PhCH₂CH₂CH:CHCH₂Cl and (Z)-PhMe₂SiCH:CHCH₂Cl with alkylboranes generated from terminal alkenes such as 1-allyl-3,4-dimethoxybenzene and 1-octene and the dimer of 9-borabicyclo[3.3.1]nonane in the presence of CuOTf•0.5PhMe and nonracemic biaryldiphosphine ligands using potassium methanolate or ethanolate in 1,4-dioxane/CH₂Cl₂ or THF/CH₂Cl₂ mixtures Using copper catalysts, enantioenriched chiral products containing tertiary or quaternary carbon stereogenic centers branched with functionalized sp³-alkyl groups were prepared; various functional groups (acetals, esters, silyl ethers, phthalimide) were tolerated. The wide availability of alkylboranes by hydroboration of alkenes is an attractive feature of these transformations. A reaction pathway involving addition and elimination of a neutral alkylcopper(I) species with the allyl chloride substrate is proposed. 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: 352655-61-9Name: (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. 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.Name: (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

Iron-catalyzed olefin carbometalation was written by Nakamura, Masaharu;Hirai, Atsushi;Nakamura, Eiichi. And the article was included in Journal of the American Chemical Society in 2000.Reference of 55700-44-2 This article mentions the following:

Iron catalysts, involving a new (soft)phosphine/(hard)diamine ligand system for a iron/zinc bimetallic reagent, are effective for promotion of olefin enantioselective carbometalation. Thus, treatment of the cyclopropenone acetal I with RMgBr (R = Ph, allyl, Me, PhCH₂CH₂) or R₂Zn (R¹ = Et, pentyl) in THF containing FeCl₃ and subsequent hydrolysis with aqueous NH₄Cl gave the cyclopropanone acetals II (R = Ph, allyl, Me, PhCH₂CH₂, Et, pentyl; R¹ = H) in 66-96% yields. Similar treatment of I with PhMgBr and then with electrophiles, e.g. MeI, trans-cinnamyl chloride, or benzaldehyde, gave disubstituted cyclopropanes, e.g. II [R = Ph; R¹ = Me, PhCH(OH), (E)-PhCH:CHCH₂]. Enantioselective reaction of I with Et₂Zn in toluene containing FeCl₃, tetramethylethylenediamine, and (R)-2,2′-bis[bis(4-methylphenyl)phosphino]-1,1′-binaphthyl [(R)-p-tol-BINAP] for 6 days at -10° and one day at 0° followed by hydrolysis with aqueous NH₄Cl gave (R)-I (R¹ = Et; R² = H) in 64% yield and 90% ee. In the experiment, the researchers used many compounds, for example, (R)-N,N-Dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine (cas: 55700-44-2Reference of 55700-44-2).

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

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Rhodium-Catalyzed Asymmetric Synthesis of Indanones: Development of a New “Axially Chiral” Bisphosphine Ligand was written by Shintani, Ryo;Yashio, Keiji;Nakamura, Tomoaki;Okamoto, Kazuhiro;Shimada, Toyoshi;Hayashi, Tamio. And the article was included in Journal of the American Chemical Society in 2006.Application of 133545-16-1 This article mentions the following:

A rhodium-catalyzed asym. isomerization of racemic α-arylpropargyl alcs. to β-chiral indanones has been developed. High enantioselectivity has been realized by the use of a newly developed axially chiral bisphosphine ligand. This ligand is unique in the sense that its axial chirality is fixed to a single configuration upon complexation to a transition metal due to other chiral axes existing within the same mol. 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. At present, the synthesis of new chiral phosphines designed specifically for nucleophilic organocatalysis remains a significant challenge. 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

Construction of quaternary stereogenic carbon centers through copper-catalyzed enantioselective allylic cross-coupling with alkylboranes was written by Hojoh, Kentaro;Shido, Yoshinori;Ohmiya, Hirohisa;Sawamura, Masaya. And the article was included in Angewandte Chemie, International Edition in 2014.Computed Properties of C74H104O6P2 This article mentions the following:

A combination of an in situ generated chiral Cu(I)/DTBM-MeO-BIPHEP [DTBM = 3,5-(Me₃C)₂C₆H₂-4-OMe] catalyst system and EtOK enabled the enantioselective S_N2′-type allylic cross-coupling between alkylborane reagents and γ,γ-disubstituted primary allyl chlorides with enantiocontrol at a useful level. The reaction generates a stereogenic quaternary carbon center having 3 sp³-alkyl groups and a vinyl group. This protocol allowed the use of terminal alkenes as nucleophile precursors, thus representing a formal reductive allylic cross-coupling of terminal alkenes. A reaction pathway involving addition/elimination of a neutral alkylcopper(I) species with the allyl chloride substrate is proposed. 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: 352655-61-9Computed Properties of C74H104O6P2).

(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. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Effective chiral catalysts for nucleophilic phosphine catalysis are scarce, seriously limiting the development of asymmetric variants. Computed Properties of C74H104O6P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Development of a Second Generation Palladium Catalyst System for the Aminocarbonylation of Aryl Halides with CO and Ammonia was written by Wu, Xiao-Feng;Neumann, Helfried;Beller, Matthias. And the article was included in Chemistry – An Asian Journal in 2010.SDS of cas: 37002-48-5 This article mentions the following:

An improved and general Pd(OAc)₂/dppf-catalyzed aminocarbonylation of aryl and heteroaryl bromides and chlorides with CO and ammonia has been established. Primary amides are accessible under comparably mild conditions in good yield. 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. 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.SDS of cas: 37002-48-5

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

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