scholarly journals Bond Forming Reactions Involving Isocyanides at Diiron Complexes

Inorganics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 25 ◽  
Author(s):  
Rita Mazzoni ◽  
Fabio Marchetti ◽  
Andrea Cingolani ◽  
Valerio Zanotti
Keyword(s):  
Transition Metal Catalysis ◽  
Organometallic Complexes ◽  
The Other ◽  
Coupling Reactions ◽  
Molecular Fragments ◽  
Carbene Ligands ◽  
Metal Catalysis ◽  
Bond Forming ◽  
Environmental Friendly ◽  
Catalyzed Reactions

The versatility of isocyanides (CNR) in organic chemistry has been tremendously enhanced by continuous advancement in transition metal catalysis. On the other hand, the urgent need for new and more sustainable synthetic strategies based on abundant and environmental-friendly metals are shifting the focus towards iron-assisted or iron-catalyzed reactions. Diiron complexes, taking advantage of peculiar activation modes and reaction profiles associated with multisite coordination, have the potential to compensate the lower activity of Fe compared to other transition metals, in order to activate CNR ligands. A number of reactions reported in the literature shows that diiron organometallic complexes can effectively assist and promote most of the “classic” isocyanide transformations, including CNR conversion into carbyne and carbene ligands, CNR insertion, and coupling reactions with other active molecular fragments in a cascade sequence. The aim is to evidence the potential offered by diiron coordination of isocyanides for the development of new and more sustainable synthetic strategies for the construction of complex molecular architectures.

Double C–H Activation for the C–C bond Formation Reactions

2018 ◽  
Vol 15 (7) ◽  
pp. 882-903 ◽  
Author(s):  
Jialin Liu ◽  
Xiaoyu Xiong ◽  
Jie Chen ◽  
Yuntao Wang ◽  
Ranran Zhu ◽  
...  
Keyword(s):  
Molecular Design ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Hypervalent Iodine ◽  
Coupling Reactions ◽  
Bond Forming ◽  
Direct Functionalization ◽  
Catalyzed Reactions ◽  
Medium Ring ◽  
Bond Formation Reactions

Background: Among the numerous bond-forming patterns, C–C bond formation is one of the most useful tools for building molecules for the chemical industry as well as life sciences. Recently, one of the most challenging topics is the study of the direct coupling reactions via multiple C–H bond cleavage/activation processes. A number of excellent reviews on modern C–H direct functionalization have been reported by Bergman, Bercaw, Yu and others in recent years. Among the large number of available methodologies, Pdcatalyzed reactions and hypervalent iodine reagent mediated reactions represent the most popular metal and non-metal involved transformations. However, the comprehensive summary of the comparison of metal and non-metal mediated transformations is still not available. Objective: The review focuses on comparing these two types of reactions (Pd-catalyzed reactions and hypervalent iodine reagent mediated reactions) based on the ways of forming new C–C bonds, as well as the scope and limitations on the demonstration of their synthetic applications. Conclusion: Comparing the Pd-catalyzed strategies and hypervalent iodine reagent mediated methodologies for the direct C–C bond formation from activation of C-H bonds, we clearly noticed that both strategies are powerful tools for directly obtaining the corresponding pruducts. On one hand, the hypervalent iodine reagents mediated reactions are normally under mild conditions and give the molecular diversity without the presence of transition-metal, while the Pd-catalyzed approaches have a broader scope for the wide synthetic applications. On the other hand, unlike Pd-catalyzed C-C bond formation reactions, the study towards hypervalent iodine reagent mediated methodology mainly focused on the stoichiometric amount of hypervalent iodine reagent, while few catalytic reactions have been reported. Meanwhile, hypervalent iodine strategy has been proved to be more efficient in intramolecular medium-ring construction, while there are less successful examples on C(sp3)–C(sp3) bond formation. In summary, we have demonstrated a number of selected approaches for the formation of a new C–C bond under the utilization of Pd-catalyzed reaction conditions or hyperiodine reagents. The direct activations of sp2 or sp3 hybridized C–H bonds are believed to be important strategies for the future molecular design as well as useful chemical entity synthesis.

scholarly journals TiO2 Photocatalyzed C–H Bond Transformation for C–C Coupling Reactions

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 355 ◽  
Author(s):  
Yi Wang ◽  
Anan Liu ◽  
Dongge Ma ◽  
Shuhong Li ◽  
Chichong Lu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Transition Metal Catalysis ◽  
Light Irradiation ◽  
Coupling Reactions ◽  
Metal Catalysis ◽  
Bond Functionalization ◽  
Tio2 Photocatalysis ◽  
Mild Conditions

Fulfilling the direct inert C–H bond functionalization of raw materials that are earth-abundant and commercially available for the synthesis of diverse targeted organic compounds is very desirable and its implementation would mean a great reduction of the synthetic steps required for substrate prefunctionalization such as halogenation, borylation, and metalation. Successful C–H bond functionalization mainly resorts to homogeneous transition-metal catalysis, albeit sometimes suffering from poor catalyst reusability, nontrivial separation, and severe biotoxicity. TiO2 photocatalysis displays multifaceted advantages, such as strong oxidizing ability, high chemical stability and photostability, excellent reusability, and low biotoxicity. The chemical reactions started and delivered by TiO2 photocatalysts are well known to be widely used in photocatalytic water-splitting, organic pollutant degradation, and dye-sensitized solar cells. Recently, TiO2 photocatalysis has been demonstrated to possess the unanticipated ability to trigger the transformation of inert C–H bonds for C–C, C–N, C–O, and C–X bond formation under ultraviolet light, sunlight, and even visible-light irradiation at room temperature. A few important organic products, traditionally synthesized in harsh reaction conditions and with specially functionalized group substrates, are continuously reported to be realized by TiO2 photocatalysis with simple starting materials under very mild conditions. This prominent advantage—the capability of utilizing cheap and readily available compounds for highly selective synthesis without prefunctionalized reactants such as organic halides, boronates, silanes, etc.—is attributed to the overwhelmingly powerful photo-induced hole reactivity of TiO2 photocatalysis, which does not require an elevated reaction temperature as in conventional transition-metal catalysis. Such a reaction mechanism, under typically mild conditions, is apparently different from traditional transition-metal catalysis and beyond our insights into the driving forces that transform the C–H bond for C–C bond coupling reactions. This review gives a summary of the recent progress of TiO2 photocatalytic C–H bond activation for C–C coupling reactions and discusses some model examples, especially under visible-light irradiation.

Privileged chiral N-heterocyclic carbene ligands for asymmetric transition-metal catalysis

2017 ◽  
Vol 46 (16) ◽  
pp. 4845-4854 ◽  
Author(s):  
Daniel Janssen-Müller ◽  
Christoph Schlepphorst ◽  
Frank Glorius
Keyword(s):  
Transition Metal ◽  
Asymmetric Catalysis ◽  
Transition Metal Catalysis ◽  
Carbene Ligands ◽  
Metal Catalysis

An overview on the most successful chiral N-heterocyclic carbene ligands in asymmetric catalysis is given.

Recent development of synthetic preparation methods for guanidines via transition metal catalysis

2015 ◽  
Vol 51 (2) ◽  
pp. 254-265 ◽  
Author(s):  
Wen-Xiong Zhang ◽  
Ling Xu ◽  
Zhenfeng Xi
Keyword(s):  
Transition Metal ◽  
Transition Metal Catalysis ◽  
Preparation Methods ◽  
Metal Catalysis ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

This article provides an overview of guanidine synthesis via transition-metal-catalyzed reactions including cycloaddition, guanylation and tandem guanylation/cyclization.

scholarly journals Photosensitized, energy transfer-mediated organometallic catalysis through electronically excited nickel(II)

Science ◽  
2017 ◽  
Vol 355 (6323) ◽  
pp. 380-385 ◽  
Author(s):  
Eric R. Welin ◽  
Chip Le ◽  
Daniela M. Arias-Rotondo ◽  
James K. McCusker ◽  
David W. C. MacMillan
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
Transition Metal Catalysis ◽  
Organometallic Complexes ◽  
Mechanistic Studies ◽  
Metal Catalysis ◽  
Organometallic Catalysts ◽  
Organometallic Catalysis ◽  
Electronically Excited

Transition metal catalysis has traditionally relied on organometallic complexes that can cycle through a series of ground-state oxidation levels to achieve a series of discrete yet fundamental fragment-coupling steps. The viability of excited-state organometallic catalysis via direct photoexcitation has been demonstrated. Although the utility of triplet sensitization by energy transfer has long been known as a powerful activation mode in organic photochemistry, it is surprising to recognize that photosensitization mechanisms to access excited-state organometallic catalysts have lagged far behind. Here, we demonstrate excited-state organometallic catalysis via such an activation pathway: Energy transfer from an iridium sensitizer produces an excited-state nickel complex that couples aryl halides with carboxylic acids. Detailed mechanistic studies confirm the role of photosensitization via energy transfer.

Metallaphotoredox Catalysis for Multicomponent Coupling Reactions

2021 ◽  
Author(s):  
Wen-Jing Xiao ◽  
Fu-Dong Lu ◽  
Gui-Feng He ◽  
Liang-Qiu Lu
Keyword(s):  
Transition Metal ◽  
Transition Metal Catalysis ◽  
Coupling Reactions ◽  
Complex Molecules ◽  
Metal Catalysis ◽  
Mild Conditions ◽  
Multicomponent Coupling Reactions ◽  
Multicomponent Coupling

The combination of photoredox and transition metal catalysis, which is termed metallaphotoredox catalysis, is a powerful platform for building complex molecules under mild conditions. In particular, metallaphotoredox-catalyzed multicomponent coupling reactions,...

scholarly journals Dimethylisosorbide (DMI) as a Bio-Derived Solvent for Pd-Catalyzed Cross-Coupling Reactions

Synlett ◽  
2018 ◽  
Vol 29 (17) ◽  
pp. 2293-2297 ◽  
Author(s):  
Allan Watson ◽  
Kirsty Wilson ◽  
Jane Murray ◽  
Helen Sneddon ◽  
Craig Jamieson
Keyword(s):  
Chemical Industry ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Heck Reactions ◽  
Bond Forming ◽  
Cross Coupling Reactions ◽  
Bond Forming Reactions ◽  
Palladium Catalyzed ◽  
Catalyzed Reactions

Palladium-catalyzed bond-forming reactions, such as the ­Suzuki–Miyaura and Mizoroki–Heck reactions, are some of the most broadly utilized reactions within the chemical industry. These reactions frequently employ hazardous solvents; however, to adhere to increasing sustainability pressures and restrictions regarding the use of such solvents, alternatives are highly sought after. Here we demonstrate the utility of dimethyl isosorbide (DMI) as a bio-derived solvent in several benchmark Pd-catalyzed reactions: Suzuki–Miyaura (13 examples, 62–100% yield), Mizoroki–Heck (13 examples, 47–91% yield), and Sonogashira (12 examples, 65–98% yield).

5 Metal-Catalyzed C—H Activation

2022 ◽  
Author(s):  
Y.-K. Xing ◽  
P. Fang ◽  
Z.-H. Wang ◽  
T.-S. Mei
Keyword(s):  
Transition Metal ◽  
Recent Progress ◽  
Environmentally Friendly ◽  
Transition Metal Catalysis ◽  
Metal Catalysis ◽  
Bond Forming ◽  
Organic Electrochemistry ◽  
Metal Catalyzed ◽  
Environmentally Friendly Approach ◽  
Made In

Synthetic organic electrochemistry is currently experiencing a renaissance, the merger of electrochemistry with transition-metal-catalyzed C—H activation would provide not only an environmentally friendly approach, but also offer new opportunities that conventional transition-metal catalysis may not have achieved. In this chapter, we summarize the recent progress made in catalytic C—H activation reactions using organometallic electrochemistry, including C—C, C—O, C—N, C—halogen, and C—P bond-forming reactions.

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