Tag: M.W=600-700

Williams, David R.; Shah, Akshay A. published the artcile< Total Synthesis of (+)-Ileabethoxazole via an Iron-Mediated Pauson-Khand [2 + 2 + 1] Carbocyclization>, Recommanded Product: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is ileabethoxazole total synthesis Pauson Khand carbocyclization iron; Stille cross coupling total synthesis ileabethoxazole; insertion total synthesis ileabethoxazole; asym hydride reduction copper total synthesis ileabethoxazole.

Studies describe the total synthesis of (+)-ileabethoxazole (I) using a Stille cross-coupling reaction of propargylic stannanes with 5-iodo-1,3-oxazoles to produce 1,1-disubstituted allenes. An iron-mediated [2+2+1] carbocyclization yields a novel cyclopentenone II (R = H, Me) for elaboration to I. Site-selective palladium insertion reactions allow for regiocontrolled substitutions of the heterocycle. Asym. copper hydride reductions are examined, and strategies for the formation of the central aromatic ring are discussed.

Journal of the American Chemical Society published new progress about Cyclization (Pauson-Khand [2+2+1]-carbocyclization). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Recommanded Product: (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

Kusama, Tomoya; Hirata, Shuzo published the artcile< Thermo-reversible persistent phosphorescence modulation reveals the large contribution made by rigidity to the suppression of endothermic intermolecular triplet quenching>, COA of Formula: C44H40P2, the main research area is diphenylphosphino binaphthyl triplet energy phosphorescence; diffusion constant; nonradiative deactivation; persistent room-temperature phosphorescence; phase change; reorganization energy; triplet quenching.

The suppression of thermally driven triplet deactivation is crucial for efficient persistent room-temperature phosphorescence (pRTP). However, the mechanism by which triplet deactivation occurs in metal-free mol. solids at room temperature (RT) remains unclear. Herein, we report a large pRTP intensity change in a mol. guest that depended on the reversible amorphous-crystal phase change in the mol. host, and we confirm the large contribution made by the rigidity of the host in suppressing intermol. triplet quenching in the guest. (S)-(-)-2,2′-Bis(diphenylphosphino)-1,1′- binaphthyl ((S)-BINAP) was doped as a guest into a highly purified (S)- bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl ((S)-H8-BINAP) host. It was possible to reversibly form the amorphous and crystalline states of the solid by cooling to RT from various temperatures The RTP yield (Φp) originating from the (S)-BINAP was 6.7% in the crystalline state of the (S)-H8-BINAP host, whereas it decreased to 0.31% in the amorphous state. Arrhenius plots showing the rate of nonradiative deactivation from the lowest triplet excited state (T1) of the amorphous and crystalline solids indicated that the large difference in Φp between the crystalline and amorphous states was mostly due to the discrepancy in the magnitude of quenching of intermol. triplet energy transfer from the (S)-BINAP guest to the (S)-H8-BINAP host. Controlled analyses of the T1 energy of the guest and host, and of the reorganization energy of the intermol. triplet energy transfer from the guest to the host, confirmed that the large difference in intermol. triplet quenching was due to the discrepancy in the magnitude of the diffusion constant of the (S)-H8-BINAP host between its amorphous and crystalline states. Quantification of both the T1 energy and the diffusion constant of mols. used in solid materials is crucial for a meaningful discussion of the intermol. triplet deactivation of various metal-free solid materials.

Frontiers in Chemistry (Lausanne, Switzerland) published new progress about Crystallinity. 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

Hato, Yoshio; Oonishi, Yoshihiro; Yamamoto, Yasunori; Nakajima, Kiyohiko; Sato, Yoshihiro published the artcile< Stereoselective Construction of Spiro-Fused Tricyclic Frameworks by Sequential Reaction of Enynes, Imines, and Diazoalkenes with Rh(I) and Rh(II) Catalysts>, Application of C44H40P2, the main research area is stereoselective spiro fused tricyclic compound; rhodium catalyst imine tethered enyne reaction diazoalkene.

Stereoselective construction of spiro-fused tricyclic compounds from enynes having a tethered imine with diazoalkenes was achieved by Rh(I)- and Rh(II)-catalyzed sequential reactions. This method consists of three reactions, i.e., Rh(I)-catalyzed cyclization of enynes with a tethered imine, Rh(II)-catalyzed cyclopropanation with diazoalkenes, and Cope rearrangement. Notably, the sequential reactions can be operated in one pot, in which Rh(I) and Rh(II) catalysts work in relay without any serious catalyst deactivation to afford the spirocycles in a stereoselective manner.

Journal of Organic Chemistry published new progress about Alkenynes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 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

Alame, Mohamad; Pestre, Nathalie; de Bellefon, Claude published the artcile< Extensive re-investigations of pressure effects in rhodium-catalyzed asymmetric hydrogenations>, Electric Literature of 325168-88-5, the main research area is pressure effect rhodium catalysis asym hydrogenation.

The catalytic hydrogenation of three prochiral substrates Me Z-α-acetamidocinnamate (MAC), Me 2-acetamidoacrylate (M-Acrylate) and Et 4-methyl-3-acetamido-2-propanoate (E-EMAP) with rhodium precursors complexed with chiral diphosphines is reported at 1-30 bar hydrogen pressure. A library of 56 chiral diphosphines, including 23 BINAP derivatives, 7 JOSIPHOS, 5 BIPHEP, 3 DUPHOS derivatives, and 18 other ligands, was used. While it was generally accepted that high hydrogen pressure would result in lower ees, it is now demonstrated on a statistical basis that an equivalent distribution between beneficial and detrimental pressure effects on ee prevails and that the hydrogen pressure effect on enantioselectivity is not an isolated phenomenon since more than 33% of the reaction systems studied are strongly affected. In some case, the enantioselectivity can be improved up to 97% just by applying a higher hydrogen pressure. Extension of these conclusions to other non-chiral reagents is proposed.

Advanced Synthesis & Catalysis published new progress about Hydrogenation. 325168-88-5 belongs to class chiral-phosphine-ligands, and the molecular formula is C48H50P2, Electric Literature 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

Zhu, Guang-Yu; Zhai, Tong-Yi; Li, Xiao; Shi, Chong-Yang; Zhu, Xin-Qi; Ye, Long-Wu published the artcile< Copper-Catalyzed Cyclization of N-Propargyl Ynamides with Borane Adducts through B-H Bond Insertion>, Reference of 139139-86-9, the main research area is propargyl ynamide preparation copper catalyzed borylation cyclization borane adduct; amineboranyl arylpyrrole derivative preparation crystal structure borylation oxidation; mol structure amineboranyl arylpyrrole derivative; amine boranyl aryl pyrrole derivative preparation.

An efficient Cu-catalyzed cyclization of N-propargyl ynamides with borane adducts through B-H bond insertion was developed. Valuable organoboron compounds are constructed in generally good yields with a wide substrate scope and good functional group tolerance under mild reaction conditions. Importantly, this protocol via vinyl cation intermediates constitutes a novel way of B-H bond insertion.

Organic Letters published new progress about Boranes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation) ((amine-boranyl)(aryl)pyrrole derivatives). 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

Burk, Mark J.; Hems, William; Herzberg, Daniela; Malan, Christophe; Zanotti-Gerosa, Antonio published the artcile< A Catalyst for Efficient and Highly Enantioselective Hydrogenation of Aromatic, Heteroaromatic, and α,β-Unsaturated Ketones>, Category: chiral-phosphine-ligands, the main research area is enantioselective hydrogenation ketone ruthenium catalyst.

PhanePhos-ruthenium-diamine complexes catalyze the asym. hydrogenation of a wide range of aromatic, heteroaromatic, and α,β-unsaturated ketones with high activity and excellent enantioselectivity.

Organic Letters published new progress about Alcohols Role: SPN (Synthetic Preparation), PREP (Preparation). 325168-88-5 belongs to class chiral-phosphine-ligands, and the molecular formula is C48H50P2, Category: chiral-phosphine-ligands.

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

Shibata, Takanori; Takami, Kyoko; Kawachi, Ai published the artcile< Rh-Catalyzed Enantioselective [2+2] Cycloaddition of Alkynyl Esters and Norbornene Derivatives>, Quality Control of 139139-93-8, the main research area is cyclobutene tetracyclic tricyclic asym synthesis; asym synthesis tricyclononenecarboxylate; rhodium catalyst enantioselective cycloaddition alkynyl ester norbornene.

The enantioselective [2+2] cycloaddition of alkynes possessing an ester functionality, e.g. PhCCCO2Me, and norbornene derivatives proceeded efficiently using a chiral rhodium catalyst. The resulting chiral tri- and tetracyclic cyclobutenes were obtained in moderate to high ee.

Organic Letters published new progress about [2+2] Cycloaddition reaction, stereoselective. 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

Imase, Hidetomo; Suda, Takeshi; Shibata, Yu; Noguchi, Keiichi; Hirano, Masao; Tanaka, Ken published the artcile< Highly enantioselective construction of axial chirality by palladium-catalyzed cycloisomerization of N-alkenyl arylethynylamides>, Computed Properties of 139139-86-9, the main research area is axial chiral arylpyridone derivative asym preparation; alkenyl arylethynylamide preparation asym cycloisomerization palladium phosphine; palladium chiral phosphine asym cycloisomerization catalyst.

A cationic palladium(II)/(S)-xyl-Segphos complex catalyzes enantioselective cycloisomerizations of N-alkenyl arylethynylamides leading to axially chiral 4-aryl-2-pyridones in high yields with high ee values. The present catalysis represents the first enantioselective construction of axial chirality by the transition-metal-catalyzed cycloisomerization.

Organic Letters published new progress about Cycloisomerization. 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Computed Properties 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

Tsuchikama, Kyoji; Hashimoto, Yu-ki; Endo, Kohei; Shibata, Takanori published the artcile< Iridium-Catalyzed Selective Synthesis of 4-Substituted Benzofurans and Indoles via Directed Cyclodehydration>, Synthetic Route of 139139-93-8, the main research area is iridium catalyst aryloxy arylamino ketone cyclization benzofuran indole preparation.

A directed cyclization-dehydration cascade of α-aryloxy ketones and α-arylamino ketones was efficiently catalyzed by a cationic iridium-BINAP complex, which afforded various types of 4-substituted benzofurans and indoles in high yields with complete regioselectivity. The newly developed protocol also enabled the enantioselective preparation of chiral 4-acetyloxindole using a chiral iridium catalyst.

Advanced Synthesis & Catalysis published new progress about Cyclization. 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Synthetic Route 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

Senda, Taichi; Ogasawara, Masamichi; Hayashi, Tamio published the artcile< Rhodium-Catalyzed Asymmetric 1,4-Addition of Organoboron Reagents to 5,6-Dihydro-2(1H)-pyridinones. Asymmetric Synthesis of 4-Aryl-2-piperidinones>, Recommanded Product: (R)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is asym synthesis arylpiperidinone; stereoselective addition organoboron pyridinone; paroxetine intermediate stereoselective preparation.

Catalytic asym. synthesis of 4-aryl-2-piperidinones was realized by asym. 1,4-addition of arylboron reagents to 5,6-dihydro-2(1H)-pyridinones in the presence of a chiral bisphosphine-rhodium catalyst. In the reaction introducing the 4-fluorophenyl group, the use of 4-fluorophenylboroxine and 1 equiv (to boron) of water at 40°C gave the highest yield of the arylation product with high enantioselectivity (98% ee). The (R)-4-(4-fluorophenyl)-2-piperidinone obtained is a key intermediate for the synthesis of (-)-Paroxetine.

Journal of Organic Chemistry published new progress about Addition reaction catalysts, stereoselective. 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