Catalytic Asymmetric Cyclopropanation with Diazooxindole

Awata, Atsuko; Arai, Takayoshi

doi:10.1055/s-0032-1317746

Cited by 13 publications

(4 citation statements)

References 3 publications

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“…In detail, styrene (0.75 mmol) and diazooxindole (0.15 mmol) in 3 mL of an appropriate solvent (here we focused on dichloromethane (DCM), dichloroethane (DCE) and toluene according to refs. [38][39]) were added to a two-necked round-bottom flask equipped with a magnetic stir bar followed by addition of a specific amount (1.50 or 3.75 μmol Rh 2 ) of the chiral dirhodium catalyst. The reaction was performed under Ar atmosphere at 0°C.…”

Section: Catalytic Asymmetric Cyclopropanationmentioning

confidence: 99%

“…For example, spiro-cyclopropyloxindole compounds can be synthesized by cyclopropanation of diazooxindoles with olefins employing chiral dirhodium catalysts. [38][39] Such spiro cyclopropyloxindoles constitute an important group of heterocycles with potential application in medical research, including the use as potent HIV inhibitor [40][41][42] and antitumor agent. [43][44][45][46] Despite their high activity and selectivity, the unsatisfactory catalyst recovery and recycling of the costly manufactured chiral dirhodium catalysts is the primary limiting factor for their application in chemical industry.…”

Section: Introductionmentioning

confidence: 99%

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Dirhodium Coordination Polymers for Asymmetric Cyclopropanation of Diazooxindoles with Olefins: Synthesis and Spectroscopic Analysis

Rösler

Herr

et al. 2020

ChemPlusChem

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A facile approach is reported for the preparation of dirhodium coordination polymers [Rh2(L1)2]n (Rh2‐L1) and [Rh2(L2)2]n (Rh2‐L2; L1=N,N’‐(pyromellitoyl)‐bis‐L‐phenylalanine diacid anion, L2=bis‐N,N’‐(L‐phenylalanyl) naphthalene‐1,4,5,8‐tetracarboxylate diimide) from chiral dicarboxylic acids by ligand exchange. Multiple techniques including FTIR, XPS, and 1H→13C CP MAS NMR spectroscopy reveal the formation of the coordination polymers. 19F MAS NMR was utilized to investigate the remaining TFA groups in the obtained coordination polymers, and demonstrated near‐quantitative ligand exchange. DR‐UV‐vis and XPS confirm the oxidation state of the Rh center and that the Rh‐single bond in the dirhodium node is maintained in the synthesis of Rh2‐L1 and Rh2‐L2. Both coordination polymers exhibit excellent catalytic performance in the asymmetric cyclopropanation reaction between styrene and diazooxindole. The catalysts can be easily recycled and reused without significant reduction in their catalytic efficiency.

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Section: Catalytic Asymmetric Cyclopropanationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dirhodium Coordination Polymers for Asymmetric Cyclopropanation of Diazooxindoles with Olefins: Synthesis and Spectroscopic Analysis

Rösler

Herr

et al. 2020

ChemPlusChem

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“…Dirhodium complexes are bimetallic compounds with one Rh–Rh bond and four bridging ligands at equatorial positions, displaying a unique paddle-wheel structure. − By virtue of the distinct structure and high stability, they exhibited versatile and powerful catalytic properties for a diverse array of carbine transformations of diazocarbony compounds, including cyclopropanation, C–H activation, olefins aziridination, and ylide formation. − The variety of reactions has made dirhodium complexes extremely attractive in the syntheses of important organic compounds as active pharmaceutical ingredients. − In this context, spiro -cyclopropyloxindoles constitute a unique motif of heterocycles with potential applications as potent HIV inhibitor, antitumor agent, and useful building blocks, which can be synthesized by cyclopropanation of diazooxindoles with alkenes employing dirhodium, ruthenium, mercury, and gold catalysts. − Compared to ruthenium, mercury, and gold catalysts, the dirhodium catalysts are more reactive toward alkyl-substituted alkene substrates in the cyclopropanation reaction. − However, the unsatisfactory catalyst recyclability and reusability of homogeneous dirhodium catalysts are the primary restricting factors for their practical application in industrial processes.…”

Section: Introductionmentioning

confidence: 99%

Self-Supported Chiral Dirhodium Organic Frameworks Enables Efficient Asymmetric Cyclopropanation

Li,

Jiang,

Zhu

et al. 2024

ACS Appl. Mater. Interfaces

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The development of heterogeneous chiral dirhodium catalysts for fabricating important bioactive substances and reducing the loss of noble metals has long been of significant interest. However, there still remains formidable synthetic challenges since it requires multiple steps of the synthetic process, and rhodium is easily leached from solid materials during the reaction. Here, we demonstrated a self-supported strategy based on the Suzuki−Miyaura coupling reaction to construct two chiral dirhodium organic frameworks for heterogeneous asymmetric catalysis. The synthetic approach is simple and efficient since it requires only a small number of preparation steps and does not require any catalyst supporting materials. The obtained chiral dirhodium materials can be highly efficient and recyclable heterogeneous catalysts for asymmetric cyclopropanation between diazooxindole and alkenes. Importantly, Rh 2 -MOCP-2 exhibited almost similar catalytic performance compared to homogeneous catalyst Rh 2 (S-Br-NTTL) 4 . The afforded catalytic performance (93.9% yield with 80.9% ee) highly surpasses previous heterogeneous dirhodium catalysts reported to date.

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“…The cyclopropanation of oxindole compounds is a facile method employed for the preparation of the spiro-cyclopropyloxindoles. , Lewis acid catalysts containing Rh(II), − Au(I), , Hg(II), Cu(II), , and Co(II) , have been shown to be effective in the catalysis of olefin cyclopropanation with diazo reagents, affording the optically active spiro-cyclopropyloxindoles with high stereoselectivity. The reactions involved the formation of metal-stabilized donor/acceptor carbenoid species, and the catalytic properties could be readily modulated by varying the ligands and counteranions .…”

Section: Introductionmentioning

confidence: 99%

Mechanism and Selectivity of Cyclopropanation of 3-Alkenyl-oxindoles with Sulfoxonium Ylides Catalyzed by a Chiral N,N′-Dioxide–Mg(II) Complex

Meng

Wang

et al. 2021

J. Org. Chem.

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The mechanism and stereoselectivity of an asymmetric cyclopropanation reaction between 3-alkenyl-oxindole and sulfoxonium ylide catalyzed by a chiral N,N′dioxide−Mg(II) complex were explored using the B3LYP-D3(BJ) functional and the def2-TZVP basis set. The noncatalytic reaction occurred via a stepwise mechanism, with activation barriers of 21.6−23.5 kcal mol −1 . The C 2 −C α bond formed followed by the carbanion S N 2 substitution, constructing a three-membered ring in spiro-cyclopropyl oxindoles, accompanied by the release of dimethylsulfoxide. The electron-withdrawing Nprotecting t-butyloxy carbonyl (Boc) and acetyl (Ac) groups in isatin enhanced the local electrophilicity of the C2 atom and the repulsion between the two COPh groups in the reactants, contributing to high reactivity as well as good diastereoselectivity results. The N-Boc-3-phenacylideneoxindole coordinated to the chiral ligand (L-PiPr 2 ) in a bidentate fashion, forming a hexacoordinate-Mg(II) complex as the reactive species. The origin of enantioselectivity was from the shielding effect of 2,6-diisopropylphenyl groups in the ligand toward the si-face of oxindole. The repulsion between the SO(CH 3 ) 2 and COPh groups in 3-alkenyl-oxindole and the neighboring ortho-iPr group in the ligand directed the re-face of ylide to attack the re-face of oxindole preferably, contributing to the high diastereoselectivity of the product. A metal-ion−ligand matching relationship was important for a good asymmetric induction effect of the chiral N,N′-dioxide−metal catalyst. A large chiral cavity in the Zn(II) catalyst weakened the shielding effect of 2,6-diisopropylphenyl groups in the ligand toward the prochiral face of oxindole, leading to inferior enantioselectivity observed in the experiment.

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Catalytic Asymmetric Cyclopropanation with Diazooxindole

Cited by 13 publications

References 3 publications

Dirhodium Coordination Polymers for Asymmetric Cyclopropanation of Diazooxindoles with Olefins: Synthesis and Spectroscopic Analysis

Dirhodium Coordination Polymers for Asymmetric Cyclopropanation of Diazooxindoles with Olefins: Synthesis and Spectroscopic Analysis

Self-Supported Chiral Dirhodium Organic Frameworks Enables Efficient Asymmetric Cyclopropanation

Mechanism and Selectivity of Cyclopropanation of 3-Alkenyl-oxindoles with Sulfoxonium Ylides Catalyzed by a Chiral N,N′-Dioxide–Mg(II) Complex

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