Iron–Copper Dual Catalysis Enabling C−C and C−X (X=N, B, P, S, Sn) Bond Formation

Huo, Lu-Qiong; Shi, Lili; Fu, Junkai

doi:10.1002/ejoc.202200454

Cited by 5 publications

(6 citation statements)

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“…During individual fish development, changes occur in its food intake and digestive organs (Wootton, 1998). Many studies have shown that as fish grow and develop, their feeding habits are generally transformed (Graeb et al, 2005;Yan et al, 2011;Huo et al, 2014;Su et al, 2015;Sarker et al, 2023). Different sizes of fish have different food preferences (different prey types and sizes), which are related to the strategy of predation (Graeb et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

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The feeding habits of the Amur whitefish Coregonus ussuriensis in the Amur River, China

Wang,

Huo,

et al. 2023

Front. Environ. Sci.

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To study their feeding habits, Coregonus ussuriensis samples were collected seasonally in the Amur River, China. A total of 574 samples were collected, including 200 individuals with empty stomachs. The stomach contents of the remaining 374 samples were identified, counted, weighed, and analyzed. The results showed that the vacuity rate of Coregonus ussuriensis was 34.84% in total; the rates in summer and autumn were higher than in spring and winter. Prey items could be divided into three categories: fish, benthos, and mammals, with 62 taxonomic units. Of these, fish had the highest relative importance index (IRI), followed by benthos and mammals. Specifically, Exopalaemon modestus was the dominant species among the food species of Coregonus ussuriensis, and unidentified fish, Hydropsyche sp., Hemiculter leucisculus, Abbottina rivularis, and Saurogobio dabryi were important species. The average repletion index (RI, %) of Coregonus ussuriensis was highest in autumn (1.86), followed by winter (1.40), summer (1.26), and spring (1.02). The main food of Coregonus ussuriensis was benthos in spring and autumn, and fish in summer and winter. Cluster analysis showed that, according to the similarity level of the bait biological composition, the fork length group samples of Coregonus ussuriensis could be divided into three groups: 210–330 mm, 330–450 mm, and >450 mm. The highest IRI% of feed organisms in these three groups of samples were fish (73.67%), benthos (75.12%), and benthos (94.46%), respectively. It can be observed that with the growth of the fork length of Coregonus ussuriensis, the importance of benthos in its diet increases. The results of an RDA analysis on the relationship between main bait organisms and various factors indicated that season, river level, river width, and fish size have a significant impact on bait organisms and a positive or negative impact on the quality scores of some bait species. This study filled the gap in biological research on the feeding ecology of Coregonus ussuriensis and laid a research foundation for ecological research on this species and its resource protection and aquaculture.

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Section: Discussionmentioning

confidence: 99%

“…The stomach content analysis is a traditional method for studying fish feeding, and it is also the most direct and effective. It can accurately determine specific types of diet and is widely used in studies of fish feeding ecology (Yan et al, 2011;Huo et al, 2014;Ma et al, 2014;Sui et al, 2021;Sarker et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

The feeding habits of the Amur whitefish Coregonus ussuriensis in the Amur River, China

Wang,

Huo,

et al. 2023

Front. Environ. Sci.

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“…Although most bimetallic catalysts reported until date are based on heterogeneous catalysis, 22−24 reports of their discrete molecular species being involved and detected in homogeneous catalysis, especially in C−H activation processes. 25,26 A study of the literature with respect to directing group assistance leads to the conclusion that when there is scope for two different sites for functionalization, the observed selectivity is dependent on several factors, such as the nature of the directing group and the catalyst employed. The directing groups at C3 reported to date are linked to the indole via C−C bonds and involve indolyl imines, aldehydes, ketones, carboxylic acids, or their esters.…”

Section: ■ Introductionmentioning

confidence: 99%

“…A bimetallic catalyst involves two metals acting synergistically to provide a better yield and selectivity of the product compared to those of any one of them. Although most bimetallic catalysts reported until date are based on heterogeneous catalysis, − there are some reports of their discrete molecular species being involved and detected in homogeneous catalysis, especially in C–H activation processes. , …”

Section: Introductionmentioning

confidence: 99%

Acetoxy Group-Directed Regioselective C2 Alkenylation of Indoles via Pd–Ag Bimetallic Catalysis

Paul,

Sengupta,

Sarkar

et al. 2023

J. Org. Chem.

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Regioselective C−H functionalizations of indoles reported to date with directing groups at C3 mainly rely on functional groups that are linked to the indole via C−C bonds. However, groups that are linked to the indole core by C−X linkages are also attractive due to the possibility of further modifications of the C−X bond. Herein, we report a 3-acetoxy directing group for the regioselective C2 alkenylation of indoles via a C−H activation-based, cross-dehydrogenative, oxidative Heck-type reaction. The reaction is catalyzed by Pd(II) and Ag(I) with stoichiometric Cu(II) as the oxidant and provides the 2-alkenylated indoles in yields of 52−84%. The reaction conditions are compatible with several functional groups at different positions as well as different N-protecting groups or free NH groups on the indole core. With respect to the alkene coupling partners, the reactions are successful with acrylates, vinyl sulfates, and phosphates. Specifically designed experiments, as well as density functional theory (DFT) computational studies, reveal that a heterodinuclear [Pd(μ-OAc) 3 Ag] bimetallic species is the actual catalyst responsible for the C−H alkenylation. A mechanistic path involving this catalytic species was also found to be favorable over other possible pathways for explaining the observed regioselectivity through DFT studies.

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“…[3] Among them, dual-catalysis wherein two catalysts cooperatively activate reacting partners in the discrete catalytic cycles appears to be very promising strategy. [4] Such cooperative dual catalysis has shown unprecedented reactivity for the functionalization of CÀ H bonds in various synthetically challenging conversions. [5] Recently, cooperative bimetallic mechanism involving two distinct palladium centers has also been explored.…”

Section: Introductionmentioning

confidence: 99%

Ligand Combination Approach in Pd‐Catalyzed Direct C−H Arylation of Benzothiazole and Benzoxazole

Bakare,

Patil

2023

Eur J Org Chem

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We demonstrate the use of ligand combination approach in the Pd catalyzed direct C‐H arylation of benzothiazole and benzoxazole. The combination of two ligands phenanthroline monohydrate (Phen.H2O) and triphenylphosphine (PPh3) with Pd‐catalyst have offered the best catalytic properties in the C‐H bond arylation reactions than either of two ligands employed separately in the reactions. This protocol exhibits a wide substrate scope affording C2 arylated benzothiazole and benzoxazole derivatives in excellent yields. Mechanistic studies including kinetic isotope effect (KIE), H/D exchange and competition experiments show that the C‐H bond activation of benzothiazole/benzoxazole is very facile under reaction conditions. Furthermore, different mechanistic pathways originated from the catalytically active species such as Pd(η2‐dba)L (dba = dibenzylidene acetone) and Pd(PPh3)2 were investigated using computational methods. The computational results suggest that the generation of catalytically active species from Pd2(dba)3 is endoergic process and Phen ligand can initiate this step. On the other hand, the presence of PPh3 could be crucial for the oxidative addition of aryl halides which is the rate‐determining step of the reaction.

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Iron–Copper Dual Catalysis Enabling C−C and C−X (X=N, B, P, S, Sn) Bond Formation

Cited by 5 publications

References 116 publications

The feeding habits of the Amur whitefish Coregonus ussuriensis in the Amur River, China

The feeding habits of the Amur whitefish Coregonus ussuriensis in the Amur River, China

Acetoxy Group-Directed Regioselective C2 Alkenylation of Indoles via Pd–Ag Bimetallic Catalysis

Ligand Combination Approach in Pd‐Catalyzed Direct C−H Arylation of Benzothiazole and Benzoxazole

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