Electrochemistry-Enabled Ir-Catalyzed Vinylic C–H Functionalization

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(48), P. 18970 - 18976

Published: Nov. 12, 2019

Synergistic use of electrochemistry and organometallic catalysis has emerged as a powerful tool for site-selective C–H functionalization, yet this type transformation thus far mainly been limited to arene functionalization. Herein, we report the development electrochemical vinylic functionalization acrylic acids with alkynes. In reaction an iridium catalyst enables C–H/O–H alkyne annulation, affording α-pyrones good excellent yields in undivided cell. Preliminary mechanistic studies show that anodic oxidation is crucial releasing product regeneration Ir(III) intermediate from diene-Ir(I) complex, which coordinatively saturated, 18-electron complex. Importantly, common chemical oxidants such Ag(I) or Cu(II) did not give significant amounts desired absence electrical current under otherwise identical conditions.

Language: Английский

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Ruthenium-Catalyzed Enantioselective C–H Functionalization: A Practical Access to Optically Active Indoline Derivatives

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(40), P. 15730 - 15736

Published: Sept. 19, 2019

Ru(II)-catalyzed enantioselective C–H activation/hydroarylation has been developed for the first time, allowing highly synthesis of indoline derivatives via catalytic activation. Commercially available Ru(II) arene complexes and chiral α-methylamines were employed as catalysts. Based on a sterically rigidified transient directing group, multisubstituted indolines produced in up to 92% yield with 96% ee. Further transformation resulting 4-formylindoline enables access an optically active tricyclic compound that is potential biological pharmaceutical interest.

Language: Английский

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Ruthenium(II)‐Catalyzed Asymmetric Inert C−H Bond Activation Assisted by a Chiral Transient Directing Group

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(9), P. 3475 - 3479

Published: Dec. 23, 2019

Abstract A ruthenium(II)‐catalyzed asymmetric intramolecular hydroarylation assisted by a chiral transient directing group has been developed. series of 2,3‐dihydrobenzofurans bearing all‐carbon quaternary stereocenters have prepared in remarkably high yields (up to 98 %) and enantioselectivities >99 % ee ). By this methodology, novel total synthesis CB2 receptor agonist MDA7 successfully

Language: Английский

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Transition metal-catalyzed organic reactions in undivided electrochemical cells

Chemical Science, Journal Year: 2021, Volume and Issue: 12(39), P. 12866 - 12873

Published: Jan. 1, 2021

Transition metal-catalyzed organic electrochemistry is a rapidly growing research area owing in part to the ability of metal catalysts alter selectivity given transformation.

Language: Английский

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Transition Metal‐Catalyzed Intermolecular Cascade C−H Activation/Annulation Processes for the Synthesis of Polycycles

Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 27(1), P. 121 - 144

Published: June 12, 2020

Abstract Polycycles are abundantly present in numerous advanced chemicals, functional materials, bioactive molecules and natural products. However, the strategies for synthesis of polycycles limited to classical reactions transition metal‐catalyzed cross‐coupling reactions, requiring pre‐functionalized starting materials lengthy synthetic operations. The emergence novel approaches shows great promise fields organic/medicinal/materials chemistry. Among them, C−H activation followed by intermolecular annulation prevail, due their straightforward manner with high atom‐ step‐economy, providing rapid, concise efficient methods construction diverse polycycles. Several have been developed polycycles, relying on sequential multiple activation/annulation, or combination activation/annulation further interaction a proximal group, merger cycloaddition reaction, situ formation directing group. These attractive, efficient, step‐ atom‐economic from commercially available materials. This Minireview will provide an introduction helping researchers discover indirect connections reveal hidden opportunities. It also promote discovery activation.

Language: Английский

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gem ‐Difluoromethylene Alkyne‐Enabled Diverse C−H Functionalization and Application to the on‐DNA Synthesis of Difluorinated Isocoumarins

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(4), P. 1959 - 1966

Published: Oct. 6, 2020

Using gem-difluoromethylene alkynes as effectors, unprecedented diverse C-H activation/[4+2] annulations of simple benzoic acids are reported. The chemodivergent reaction outcomes well-tuned by Rh/Ir-catalyzed system; in the RhIII catalysis, 3-alkenyl-1H-isochromen-1-one and 3,4-dialkylideneisochroman-1-one skeletons afforded a solvent-dependent manner whereas difluoromethylene-substituted 1H-isochromen-1-ones generated under IrIII -catalyzed system. Mechanistic studies revealed that unusually double β-F eliminations fluorine effect-induced regioselective reductive elimination independently involved to enable distinct modes for divergent product formations. Besides, synthetic application both derivatization obtained diene products on-DNA synthesis DNA-tagged difluorinated isocoumarin have been demonstrated, which manifested great potential utility developed protocols.

Language: Английский

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Co(III), Rh(III) & Ir(III)‐Catalyzed Direct C−H Alkylation/Alkenylation/Arylation with Carbene Precursors

Chemistry - An Asian Journal, Journal Year: 2021, Volume and Issue: 16(5), P. 443 - 459

Published: Jan. 15, 2021

Metal carbenes play a pivotal role in transition-metal-catalyzed synthetic transfer reactions. The metal carbene is generated either from diazo compound through facile extrusion of N2 with catalyst or situ other sources like triazoles, pyriodotriazoles, sulfoxonium ylides and iodonium-ylide. On the hand, Co(III), Rh(III) & Ir(III)-catalyzed C-H functionalizations have been well established as key step to enable construction various transformations. Interestingly, recent years, merging these two concepts activation migratory insertion gained much attention, particular group 9 metal-catalyzed arene precursors via insertion. In this review, we summarize advances direct alkylation/alkenylation/arylation also discuss intermediates within catalytic cycles.

Language: Английский

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Divergent rhodium-catalyzed electrochemical vinylic C–H annulation of acrylamides with alkynes

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Feb. 10, 2021

α-Pyridones and α-pyrones are ubiquitous structural motifs found in natural products biologically active small molecules. Here, we report an Rh-catalyzed electrochemical vinylic C-H annulation of acrylamides with alkynes, affording cyclic good to excellent yield. Divergent syntheses α-pyridones imidates accomplished by employing N-phenyl N-tosyl as substrates, respectively. Additionally, regioselectivities achieved when using unsymmetrical alkynes. This process is environmentally benign compared traditional transition metal-catalyzed annulations because it avoids the use stoichiometric metal oxidants. DFT calculations elucidated reaction mechanism origins substituent-controlled chemoselectivity. The sequential activation alkyne insertion under rhodium catalysis leads seven-membered ring vinyl-rhodium intermediate. intermediate undergoes either classic neutral concerted reductive elimination produce α-pyridones, or ionic stepwise pathway imidates.

Language: Английский

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Ruthenium-Catalyzed Cycloadditions to Form Five-, Six-, and Seven-Membered Rings

Chemical Reviews, Journal Year: 2021, Volume and Issue: 121(7), P. 4045 - 4083

Published: Feb. 12, 2021

Ruthenium-catalyzed cycloadditions to form five-, six-, and seven-membered rings are summarized, including applications in natural product total synthesis. Content is organized by ring size reaction type. Coverage limited processes that involve formation of at least one C–C bond. Processes stoichiometric ruthenium or exploit as a Lewis acid (without intervention organometallic intermediates), formations occur through dehydrogenative condensation-reduction, σ-bond activation-initiated annulations do not result net reduction bond multiplicity, photochemically promoted ruthenium-catalyzed covered.

Language: Английский

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Recent advances in transition metal-catalyzed heteroannulative difunctionalization of alkenes via C–H activation for the synthesis of heterocycles

Organic Chemistry Frontiers, Journal Year: 2022, Volume and Issue: 9(8), P. 2256 - 2279

Published: Jan. 1, 2022

In this review article, we summarized recent advances in the transition metal-catalyzed heteroannulative difunctionalization of alkenes via direct C–H activation to access heterocyclic frameworks.

Language: Английский

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