Synthesis of π‐Expanded Coumarins by Ligand‐Enabled Selective C−H Functionalization

Ren, Peng; He, Zhiyuan; Xing, Tiantian; Manar, Krishna K.; Sampson, Jessica; Jin, Jian; Wang, Long; Carrow, Brad P.

doi:10.1002/adsc.202200468

Cited by 3 publications

(4 citation statements)

References 35 publications

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“…In both cases, the TOF increased as the electron-donating ability of the substituent increased. According to previous studies, this trend suggests two possible reaction mechanisms: (1) electrophilic aromatic substitution (S E Ar) mechanism and (2) base-assisted internal electrophilic substitution/electrophilic concerted metalation deprotonation (BIES − / e CMD − ) mechanism. The reactions by S E Ar mechanism generally show small KIE values; , for instance, KIE of 1.0 was reported for Rh-catalyzed intramolecular C–H bond amination .…”

Section: Resultsmentioning

confidence: 57%

RhRu Bimetallic Oxide Cluster Catalysts for Cross-Dehydrogenative Coupling of Arenes and Carboxylic Acids

Hasegawa,

Harano,

Motokura

2024

J. Am. Chem. Soc.

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Noble-metal-based bimetallic oxide clusters are promising novel catalysts. In this study, we developed carbon-supported RhRu bimetallic oxide clusters (RhRuO x /C) with a mean diameter of 1.2 nm, which showed remarkable catalytic activity for the cross-dehydrogenative coupling (CDC) of arenes and carboxylic acids with O 2 as the sole oxidant. RhRu bimetallic oxide cluster formation was confirmed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy and synchrotron X-ray absorption spectroscopy. Kinetic isotope and substituent effects indicated that arene C−H bond cleavage was the ratedetermining step and proceeded via electrophilic concerted metalation− deprotonation mechanism, with a carboxylate as an internal base. Density functional theory calculations supported the proposed mechanism and indicated that the active center for C−H bond activation was Rh(V) rather than Rh(III), while Ru enhanced the electrophilicity of the Rh(V) site by decreasing the negative charge of the surrounding oxygen atoms. Electron-rich arenes showed relatively high reactivity for the RhRuO x /C-catalyzed CDC reaction, and both aliphatic and aromatic carboxylic acids were applicable to the reaction. The RhRuO x /C catalyst is promising for the CDC reaction of arenes and carboxylic acids to produce aryl esters. This work promotes the development of noble-metal-based bimetallic oxide clusters for C−H bond activation reactions.

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Section: Resultsmentioning

confidence: 57%

RhRu Bimetallic Oxide Cluster Catalysts for Cross-Dehydrogenative Coupling of Arenes and Carboxylic Acids

Hasegawa,

Harano,

Motokura

2024

J. Am. Chem. Soc.

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“…In 2022, Peng Ren reported a new synthetic [59] route for preparing π-expanded coumarin derivatives. This method (common) goes rapidly and one of the requirements to perform it is that selective alkenylation should take place amidst CÀ H bonds in naphthol molecules by a catalyst containing palladium.…”

Section: Various Strategies For the Synthesis Of Polybeznocoumarinsmentioning

confidence: 99%

Advances in Polybenzocoumarins: Synthesis, Applications and Fluorescent Properties

Ullah,

Bukhari,

Farooq

et al. 2024

ChemistrySelect

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Polybenzocoumarins, characterized by unique structural features, have emerged as a promising class of compounds with diverse applications. In the realm of fluorescence, these molecules exhibit notable properties attributed to their extended π‐conjugation, aromaticity, and potential for intramolecular charge transfer. Diverse synthetic methodologies, including green chemistry approaches and transition‐metal‐catalyzed reactions, are discussed. The review explores the impact of structural modifications on fluorescence behavior, providing insights for designing fluorescent probes. The versatility of polybenzocoumarins makes them promising in bioimaging, sensors, and optoelectronics. This concise overview serves as a valuable resource for researchers interested in the dynamic field of polybenzocoumarin chemistry.

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“…The reaction proceeds under mild reaction conditions, with low catalyst loadings and with high selectivity. 46 Scheme 19 Selective C-H alkenylation of -naphthols with thioether/sulfonated ligand…”

Section: Scheme 17 Palladium-catalyzed Para-c-h Alkynylation Of Indolesmentioning

confidence: 99%

“…The reaction proceeds under mild reaction conditions, with low catalyst loadings and with high selectivity. 46…”

Section: Oxygen-thioether Ligandsmentioning

confidence: 99%

Recent Progress in Developing Thioether-Containing Ligands for Catalysis Applications

Bellemin-Laponnaz,

Achard

2023

Synthesis

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The ligand that stabilizes the metal center is crucial to its catalytic activity. Historically dominated by phosphorus and nitrogen, sulfur has long been little considered as a hetero element for stabilizing a potentially active metal center. However, this situation is changing and we are seeing more and more examples that incorporate this element. This review provides an overview of recent transition metal-catalyzed reactions with ligands containing neutral sulfur groups, i.e. thioethers. A selection of examples published over the last decade illustrates the diversity of applications of thioether-containing ligands and shows that sulfur should be more widely used in the development of homogeneous catalysis.

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Synthesis of π‐Expanded Coumarins by Ligand‐Enabled Selective C−H Functionalization

Cited by 3 publications

References 35 publications

RhRu Bimetallic Oxide Cluster Catalysts for Cross-Dehydrogenative Coupling of Arenes and Carboxylic Acids

RhRu Bimetallic Oxide Cluster Catalysts for Cross-Dehydrogenative Coupling of Arenes and Carboxylic Acids

Advances in Polybenzocoumarins: Synthesis, Applications and Fluorescent Properties

Recent Progress in Developing Thioether-Containing Ligands for Catalysis Applications

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