Tag: M.W=600-700

Burns, Alan R.; Lam, Hon Wai; Roy, Iain D. published the artcile< Enantioselective, rhodium-catalyzed 1,4-addition of organoboron reagents to electron-deficient alkenes>, Application of C44H40P2, the main research area is review enantioselective rhodium catalyzed organoboron addition electron deficient alkene.

A review. The enantioselective 1,4-addition of organometallic reagents to electron-deficient alkenes is one of the most important methods for carbon-carbon bond formation. Within this field, the rhodium-catalyzed 1,4-addition of organoboron reagents to electron-deficient alkenes occupies a prominent position owing to (1) the availability, stability, and functional group tolerance of organoboron reagents, (2) the wide range of acceptors that may be employed, (3) the ability of a broad range of structurally distinct families of chiral ligands to induce high enantioselectivities in the reactions, and (4) the usually mild and exptl. convenient conditions, which generally do not require any special precautions to exclude air or moisture.

Organic Reactions (Hoboken, NJ, United States) published new progress about 1,4-Addition reaction catalysts (stereoselective). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Application of C44H40P2.

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

Tanaka, Ken; Takahashi, Maho; Imase, Hidetomo; Osaka, Takuya; Noguchi, Keiichi; Hirano, Masao published the artcile< Enantioselective synthesis of α,α-disubstituted α-amino acids by Rh-catalyzed [2+2+2] cycloaddition of 1,6-diynes with protected dehydroamino acid>, Recommanded Product: (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is enantioselective synthesis amino acid rhodium BINAP catalyst cycloaddition diyne; dehydroamino acid cycloaddition diyne catalyst rhodium BINAP.

We have determined that a cationic rhodium(I)/BINAP complex catalyzes a [2+2+2] cycloaddition of 1,6-diynes with protected dehydroamino acids, leading to protected α-amino acids bearing a quaternary carbon center in high yield with high enantioselectivity. Thus, aminoisoindolecarboxylate I (Ts = tosyl) was obtained in 96% yield and 97 ee by cycloaddition reaction of TsN(CH2CCMe)2 with AcNHC(:CH2)CO2Me using Rh(cod)2BF4/(R)-BINAP.

Tetrahedron published new progress about Alkadiynes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Recommanded Product: (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

Mullen, Charles A.; Campbell, Alison N.; Gagne, Michel R. published the artcile< Asymmetric oxidative cation/olefin cyclization of polyenes: evidence for reversible cascade cyclization>, SDS of cas: 325168-88-5, the main research area is polyenol xylylphanephos platinum silver enantioselectively diastereoselectively regioselectively oxidative cyclization; fused oxygen containing heterocycle stereoselective preparation reaction determining step.

Activation of [(xylyl-phanephos)PtCl2] by silver generates an electrophilic catalyst that can enantioselectively, diastereoselectively, and regioselectively promote the stereospecific oxidative cyclization of polyene-ols. Mechanistic experiments indicate that the stereochem.-determining step is not the initial cyclization step, but rather a subsequent step in the reaction.

Angewandte Chemie, International Edition published new progress about Alkenyl alcohols Role: RCT (Reactant), RACT (Reactant or Reagent). 325168-88-5 belongs to class chiral-phosphine-ligands, and the molecular formula is C48H50P2, SDS of cas: 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

Shintani, Ryo; Duan, Wei-Liang; Hayashi, Tamio published the artcile< Rhodium-Catalyzed Asymmetric Construction of Quaternary Carbon Stereocenters: Ligand-Dependent Regiocontrol in the 1,4-Addition to Substituted Maleimides>, Reference of 139139-86-9, the main research area is rhodium complex asym addition reaction regioselectivity enantioselectivity; arylboronic acid maleimide asym addition reaction.

A rhodium-catalyzed asym. 1,4-addition of arylboronic acids of formula ArB(OH)2 (Ar = Ph, 2-naphthyl, 2-methylphenyl, 4-methoxyphenyl, 4-fluorophenyl) to substituted maleimides (I; R = Et, Me, i-Pr) has been described. The regioselectivity in this reaction is controlled by the choice of ligand (dienes or bisphosphines), and 1,4-adducts with a quaternary stereocenter (II; Ar, R = same as above) can be obtained with high regio- and enantioselectivity over 1,4-adducts with a secondary carbon center (III; Ar, R = same as above) by the use of (R)-H8-BINAP (IV). For example, I (R = Et), 3.0 equiv phenylboronic acid, 2.5 mol% divinylrhodium chloride dimer, IV (Rh/ligand = 1:1), and 0.5 equiv KOH were stirred in a 10:1 mixture of dioxane and water at 50° for 3 h to give a 87:13 mixture of II (Ar = Ph, R = Et) and III (Ar = Ph, R = Et) in 98% yield.

Journal of the American Chemical Society published new progress about Boronic acids Role: RCT (Reactant), RACT (Reactant or Reagent) (arylboronic acids). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Reference 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

Ishii, Masahiro; Mori, Fumiya; Tanaka, Ken published the artcile< Rhodium-Catalyzed [2+2+2] Cycloaddition of Diynes with Carbodiimides and Carbon Dioxide under Ambient Conditions>, COA of Formula: C44H40P2, the main research area is rhodium cycloaddition diyne carbodiimide carbon dioxide; carbodiimides; carbon dioxide; cycloaddition; diynes; rhodium.

It was established that a cationic rhodium(I)/H8-BINAP complex is able to catalyze a [2+2+2] cycloaddition of diynes with carbodiimides and carbon dioxide under ambient conditions. Enantioselective variants and regioselective variants of these reactions are also disclosed. Under optimized conditions the synthesis of the target compounds was achieved using N,N’-[(methane)tetrayl]bis[4-methylbenzenamine], N,N’-[(methane)tetrayl]bis[cyclohexanamine] (i.e., dicyclohexylcarbodiimide) and diynes, such as 2,2-bis(2-propynyl)propanedioic acid esters, 4-methyl-N,N-bis(2-propynyl)benzenesulfonamide. 3,3-bis(2-butynyl)-2,4-pentanedione as starting materials, bis[(1,2,5,6-η)-1,5-cyclooctadiene]rhodium tetrafluoroborate(1-) as a catalyst and 1,1′-(5,5′,6,6′,7,7′,8,8′-octahydro[1,1′-binaphthalene]-2,2′-diyl)bis[1,1-diphenylphosphine] (H8-BINAP) as a ligand.

Chemistry – A European Journal published new progress about Alkadiynes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, COA of Formula: C44H40P2.

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

Chang, Xin; Ma, Pei-Long; Chen, Hong-Chao; Li, Chuan-Ying; Wang, Peng published the artcile< Asymmetric Synthesis and Application of Chiral Spirosilabiindanes>, Quality Control of 139139-93-8, the main research area is alkenyldihydrosilane preparation rhodium catalyzed asym double hydrosilation spirocyclization; spirosilabiindane chiral preparation reaction aminophosphine; phosphoramidite spirosilabiindane chiral preparation catalyst ligand asym hydrogenation carboamination; crystal structure chiral spirosilabiindane diol derivative phosphoramidite; mol structure chiral spirosilabiindane diol derivative phosphoramidite; asymmetric catalysis; ligand design; silanes; spirocompounds; synthetic methods.

Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh-catalyzed asym. double hydrosilation, for the 1st time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on >10 g scale using this protocol. The potential of this new spirosilabiindane scaffold in asym. catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh-catalyzed hydrogenation and a Pd-catalyzed intramol. carboamination.

Angewandte Chemie, International Edition published new progress about Alkenes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation) (bis(alkenyl)dihydrosilanes). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Quality Control 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

Wada, Azusa; Noguchi, Keiichi; Hirano, Masao; Tanaka, Ken published the artcile< Enantioselective Synthesis of C2-Symmetric Spirobipyridine Ligands through Cationic Rh(I)/Modified-BINAP- Catalyzed Double [2 + 2 + 2] Cycloaddition>, HPLC of Formula: 139139-86-9, the main research area is bis diynenitrile rhodium chiral Segphos BINAP enantioselective double cycloaddition; sym spirobipyridine stereoselective preparation ligand; enantioselective double cycloaddition catalyst rhodium chiral Segphos BINAP.

Enantioenriched C2-sym. spirobipyridine ligands were efficiently synthesized through a cationic rhodium(I)/(R)-Segphos or (R)-H8-BINAP complex-catalyzed enantioselective intramol. double [2 + 2 + 2] cycloaddition of bis-diynenitriles.

Organic Letters published new progress about [2+2] Cycloaddition reaction, stereoselective ([2+2+2]). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, HPLC of Formula: 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

Tabuchi, Sho; Hirano, Koji; Miura, Masahiro published the artcile< Palladium-Catalyzed Asymmetric Benzylic Alkylation of Active Methylene Compounds with α-Naphthylbenzyl Carbonates and Pivalates>, Reference of 139139-93-8, the main research area is palladium catalyst asym benzylic alkylation active methylene compound; asymmetric catalysis; kinetic resolution; ligand effects; palladium; synthetic methods.

A Pd/(R)-H8-BINAP-catalyzed asym. benzylic alkylation of active methylene compounds has been developed. The reaction proceeds without the use of an external base, and the starting racemic diarylmethyl carbonates are converted into the optically active coupling products which contain the benzylic chiral stereocenter by a dynamic kinetic asym. transformation (DYKAT). Addnl., with suitable carbonates bases, the same palladium catalysis allows the corresponding pivalates to be adopted in the same DYKAT process.

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

Kashima, Kenichi; Ishii, Masahiro; Tanaka, Ken published the artcile< Synthesis of Pyridylphosphonates by Rhodium-Catalyzed [2+2+2] Cycloaddition of 1,6- and 1,7-Diynes with Diethyl Phosphorocyanidate>, Formula: C44H40P2, the main research area is diyne cycloaddition enantioselective phosphorocyanidate preparation pyridylphosphonate fluorescence.

The convenient and atom-economical synthesis of substituted bicyclic pyridylphosphonates was achieved by the cationic Rh(I)/H8-binap-complex-catalyzed [2+2+2] cycloaddition of 1,6- and 1,7-diynes with di-Et phosphorocyanidate. These reactions may proceed via an azarhodacyclopentadiene intermediate in addition to the rhodacyclopentadiene intermediate.

European Journal of Organic Chemistry published new progress about Alkadiynes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Formula: C44H40P2.

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

Okamoto, Ryuichi; Okazaki, Eri; Noguchi, Keiichi; Tanaka, Ken published the artcile< Rhodium-catalyzed olefin isomerization/enantioselective intramolecular Alder-ene reaction cascade>, HPLC of Formula: 139139-86-9, the main research area is dihydrobenzofuran dihydronaphthofuran derivative enantioselective synthesis; enyne olefin isomerization Alder ene reaction Rh chiral ligand.

The olefin isomerization/enantioselective intramol. Alder-ene reaction cascade was achieved by using a cationic rhodium(I)/(R)-BINAP complex as a catalyst. A variety of substituted dihydrobenzofurans e. g., I and dihydronaphthofurans e. g., II were obtained from phenol- or naphthol-linked 1,7-enynes, resp., with good yields and ee values.

Organic Letters published new progress about Alkenynes 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, HPLC of Formula: 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