Tag: M.W=600-700

Tanaka, Ken; Sagae, Hiromi; Toyoda, Kazuki; Hirano, Masao published the artcile< Enantioselective synthesis of planar-chiral metacyclophanes through cationic Rh(I)/modified-BINAP-catalyzed inter- and intramolecular alkyne cyclotrimerizations>, Safety of (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is enantioselective synthesis chiral metacyclophane rhodium BINAP catalyst alkyne cyclotrimerization.

We have achieved the first catalytic enantioselective synthesis of planar-chiral metacyclophanes by means of cationic Rh(I)/(S)-xyl-H8-BINAP or (R)-H8-BINAP complex-catalyzed inter- and intramol. alkyne cyclotrimerizations. This highly enantioselective catalysis represents a versatile new method for the preparation of planar-chiral metacyclophanes.

Tetrahedron published new progress about Cyclotrimerization. 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Safety of (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Felix, Ryan J.; Weber, Dieter; Gutierrez, Osvaldo; Tantillo, Dean J.; Gagne, Michel R. published the artcile< A gold-catalysed enantioselective Cope rearrangement of achiral 1,5-dienes>, Computed Properties of 325168-88-5, the main research area is gold catalysis enantioselective cope rearrangement achiral dienes.

Since the discovery of the Cope rearrangement in the 1940s, no asym. variant of the rearrangement of achiral 1,5-dienes has emerged, despite the successes that have been achieved with its heteroatom variants (Claisen, aza-Cope, and so on). This article reports the first example of an enantioselective Cope reaction that starts from an achiral diene. The new gold(I) catalyst derived from double Cl–abstraction of ((S)-3,5-xylyl-PHANEPHOS(AuCl)2), has been developed for the sigmatropic rearrangement of alkenyl-methylenecyclopropanes. The reaction proceeds at low temperature and the synthetically useful vinylcyclopropane products are obtained in high yield and enantioselectivity. D. functional theory calculations predict that: (1) the reaction proceeds via a cyclic carbenium ion intermediate, (2) the relief of strain in the methylenecyclopropane moiety provides the thermodn. driving force for the rearrangement and (3) metal complexation of the transition-state structure lowers the rearrangement barriers.

Nature Chemistry published new progress about [3,3]-Sigmatropic rearrangement. 325168-88-5 belongs to class chiral-phosphine-ligands, and the molecular formula is C48H50P2, Computed Properties of 325168-88-5.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Sekine, Keisuke; Akaishi, Dai; Konagaya, Kakeru; Ito, Shigekazu published the artcile< Copper-Catalyzed Enantioselective Hydrosilylation of gem-Difluorocyclopropenes Leading to a Stereochemical Study of the Silylated gem-Difluorocyclopropanes>, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is cyclopropene difluoro asym hydrosilylation silylboronate preparation chiral arylcyclopropane; copper chiral diphosphine monophosphine catalyst asym hydrosilylation difluorocyclopropene; asymmetric synthesis; copper catalysis; cyclopropanes; fluorine; racemization.

1-Aryl-2,2-difluorocyclopropenes ArC3HF2 undergo asym. hydrosilylation with pinBSiPhMe2 catalyzed by copper(I) complexes with mono- and bidentate chiral phosphines, affording trans-silylcyclopropanes ArCH(CF2)CHSiPhMe2 with up to 95% ee, which upon desilylation gave chiral 2-aryl-1,1-difluorocyclopropanes. Optically active cyclopropanes have been widely investigated especially from the views of pharmaceutical and agrochem. industries, and substituting one of the methylenes with the difluoromethylene unit should be promising for developing novel biol. relevant compounds and functional materials. In this paper, the copper-catalyzed enantioselective hydrosilylation of gem-difluorocyclopropenes to provide the corresponding chiral gem-difluorocyclopropanes is presented. The use of copper(I) chloride, chiral ligands including bidentate BINAPs and monodentate phosphoramidites, and silylborane Me2PhSi-Bpin accompanying sodium tert-butoxide in methanol was appropriate for the enantioselective hydrosilylation of the strained C:C double bond, and the resultant chiral difluorinated three-membered ring was unambiguously characterized. Subsequent activation of the silyl groups in enantio-enriched gem-difluorocyclopropanes showed substantial reduction of the enantiopurity, indicating cleavage of the distal C-C bond leading to the transient acyclic intermediates.

Chemistry – A European Journal published new progress about Chiral ligands Role: CAT (Catalyst Use), USES (Uses) (chiral phosphines). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Brusoe, Andrew T.; Alexanian, Erik J. published the artcile< Rhodium(I)-Catalyzed Ene-Allene-Allene [2+2+2] Cycloadditions: Stereoselective Synthesis of Complex trans-Fused Carbocycles>, Application In Synthesis of 139139-86-9, the main research area is eneallene allene rhodium catalyzed cycloaddition; hydrindane decalin stereoselective preparation four contiguous stereocenters; fused carbocycle stereoselective preparation.

The rhodium-catalyzed [2+2+2] cycloaddition of ene-allenes with allenes was utilized for the construction of a variety of trans-fused hydrindanes and decalins in a highly convergent manner, with three σ bonds, two rings, and up to four contiguous stereocenters generated in a regio- and stereoselective fashion.

Angewandte Chemie, International Edition published new progress about Allenes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Application In Synthesis of 139139-86-9.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Murai, Masahito; Takeshima, Hirotaka; Morita, Haruka; Kuninobu, Yoichiro; Takai, Kazuhiko published the artcile< Acceleration effects of phosphine ligands on the rhodium-catalyzed dehydrogenative silylation and germylation of unactivated C(sp3)-H bonds>, Synthetic Route of 139139-86-9, the main research area is diphosphine ligand rhodium catalysis dehydrogenative silylation germylation.

The current work describes the marked rate of acceleration caused by phosphine ligands on the rhodium-catalyzed dehydrogenative silylation and germylation of unactivated C(sp3)-H bonds. The reactivity was affected by the steric and electronic nature of the phosphine ligands. The use of the bulky and electron-rich diphosphine ligand (R)-DTBM-SEGPHOS was highly effective to yield the dehydrogenative silylation products selectively in the presence of a hydrogen acceptor. An appropriate choice of C2-sym. chiral diphosphine ligand enables the asym. dehydrogenative silylation via the enantioselective desymmetrization of the C(sp3)-H bond. The unprecedented catalytic germylation of C(sp3)-H bonds with dehydrogenation was also examined with the combination of the rhodium complex and a wide bite angle diphosphine ligand to provide the corresponding 2,3-dihydrobenzo[b]germoles in good yield.

Journal of Organic Chemistry published new progress about Cyclization (silylative). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Synthetic Route of 139139-86-9.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Batuecas, Maria; Luo, Junfei; Gergelitsova, Ivana; Kramer, Katrina; Whitaker, Daniel; Vitorica-Yrezabal, Inigo J.; Larrosa, Igor published the artcile< Catalytic Asymmetric C-H Arylation of (η6-Arene)Chromium Complexes: Facile Access to Planar-Chiral Phosphines>, Safety of (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is catalytic asym arylation arene chromium complex mechanism; crystal structure mol planar chiral phosphine preparation.

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.

ACS Catalysis published new progress about Arylation, stereoselective. 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Safety of (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Arao, Takafumi; Kondo, Kazuhiro; Aoyama, Toyohiko published the artcile< Asymmetric construction of quaternary carbon stereocenter by Pd-catalyzed intramolecular α-arylation>, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is quaternary carbon stereocenter palladium catalyzed intramol arylation; enantioselective indolone preparation palladium catalyzed.

The catalyst comprised of Pd(OAc)2 and H8-BINAP provides good reaction conversions for a catalytic enantioselective intramol. α-arylation of N-(2-bromophenyl)-N-methyl-2-arylpropanamides. The corresponding 3-substituted indol-2-ones are formed with up to 68% enantioselectivity.

Chemical & Pharmaceutical Bulletin published new progress about Arylation (intramol.). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Shintani, Ryo; Takagi, Chihiro; Ito, Tomoaki; Naito, Masanobu; Nozaki, Kyoko published the artcile< Rhodium-Catalyzed Asymmetric Synthesis of Silicon-Stereogenic Dibenzosiloles by Enantioselective [2+2+2] Cycloaddition>, Name: (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is rhodium catalyzed asym synthesis silicon stereogenic dibenzosilole; enantioselective cycloaddition silyl prochiral triyne internal alkyne; germanium stereogenic dibenzogermole preparation; optical property dibenzosilole dibenzogermole; crystal mol structure alkynyl dibenzosilole; asymmetric catalysis; cycloaddition; dibenzosilole; rhodium; silicon.

A rhodium-catalyzed asym. synthesis of silicon-stereogenic dibenzosiloles has been developed through a [2+2+2] cycloaddition of silicon-containing prochiral triynes with internal alkynes. High yields and enantioselectivities have been achieved by employing an axially chiral monophosphine ligand, and the present catalysis is also applicable to the asym. synthesis of a germanium-stereogenic dibenzogermole. Preliminary studies on the optical properties of these compounds are also described.

Angewandte Chemie, International Edition published new progress about Alkynes, internal Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Name: (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Najera, Carmen; de Gracia Retamosa, M.; Sansano, Jose M.; de Cozar, Abel; Cossio, Fernando P. published the artcile< Enantioselective synthesis of polysubstituted prolines by Binap-silver-catalyzed 1,3-dipolar cycloadditions>, Related Products of 139139-93-8, the main research area is polysubstituted proline derivative asym preparation; iminoester maleimide asym dipolar cycloaddition silver BINAP; silver BINAP asym dipolar cycloaddition catalyst.

The enantioselective 1,3-dipolar cycloaddition reaction of stabilized azomethine ylides, generated from iminoesters, with maleimides was efficiently achieved by intermediacy of an equimolar mixture of chiral (R)- or (S)-Binap and AgClO4. The high stability of the titled catalytic metal-complex to light exposure and its insolubility in toluene made possible its recovery and reutilization in other new process. In order to get a better understanding of the behavior of these chiral catalysts, we have carried out DFT1 calculations demonstrating the exptl. observed high enantio- and endo-selectivity through a very asynchronous transition state.

Tetrahedron: Asymmetry published new progress about 1,3-Dipolar cycloaddition reaction, stereoselective. 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Related Products of 139139-93-8.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Yoshida, Tomoka; Tajima, Yuki; Kobayashi, Masayuki; Masutomi, Koji; Noguchi, Keiichi; Tanaka, Ken published the artcile< Rhodium-Catalyzed [3+2+2] and [2+2+2] Cycloadditions of Two Alkynes with Cyclopropylideneacetamides>, Electric Literature of 139139-93-8, the main research area is cycloheptadiene diastereoselective preparation rhodium catalyst reaction mechanism; spiro cyclohexadiene stereoselective preparation rhodium catalyst reaction mechanism; alkyne unsaturated ketone cycloaddition; asymmetric catalysis; cycloaddition; heterocycles; rhodium; synthetic methods.

A cationic rhodium(I)/H8-binap complex catalyzed the [3+2+2] cycloaddition of 1,6-diynes with cyclopropylideneacetamides which produced cycloheptadiene derivatives, e.g., I, through cleavage of cyclopropane rings. A cationic rhodium(I)/(S)-binap complex catalyzed the enantioselective [2+2+2] cycloaddition of terminal alkynes, acetylenedicarboxylates, and cyclopropylideneacetamides which produced spiro-cyclohexadiene derivatives, e.g., II, which retained the cyclopropane rings.

Angewandte Chemie, International Edition published new progress about Alkynes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Electric Literature of 139139-93-8.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate