Tag: 1151.5615

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

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

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

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