Cyanomethylation of alkenes with C–H bond activation of acetonitrile: in situ generated diazonium salts as promoters without transition-metals

RSC Advances ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 522-526 ◽  
Author(s):  
Zhangqin Ni ◽  
Xin Huang ◽  
Jichao Wang ◽  
Yuanjiang Pan
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Bond Activation ◽  
Diazonium Salts

In situ generated diazonium salts were used as radical promoters for the Csp3–H functionalization of acetonitrile without photocatalyst or transition-metal.

scholarly journals Mimicking Transition Metals in Borrowing Hydrogen from Alcohol

2021 ◽  
Author(s):  
Swadhin K Mandal ◽  
Ananya Banik ◽  
Jasimuddin Ahmed ◽  
Swagata Sil
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Borrowing Hydrogen

Borrowing hydrogen from alcohol, storing it on the catalyst and subsequent transfer of the hydrogen from catalyst to an in situ generated imine is the hallmark of a transition metal...

Step-Economical C–H Activation Reactions Directed by In Situ Amidation

Synthesis ◽  
2020 ◽  
Vol 52 (21) ◽  
pp. 3211-3218
Author(s):  
Yunyun Liu ◽  
Baoli Zhao
Keyword(s):  
Transition Metal ◽  
Bond Activation ◽  
Short Review ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Directing Group ◽  
Crude Material

Owing to the inherent ability of amides to chelate transition-metal catalysts, amide-directed C–H activation reactions constitute a major tactic in directed C–H activation reactions. While the conventional procedures for these reactions usually involve prior preparation and purification of amide substrates before the C–H activation, the step economy is actually undermined by the operation of installing the directing group (DG) and related substrate purification. In this context, directed C–H activation via in situ amidation of the crude material provides a new protocol that can significantly enhance the step economy of amide-directed C–H activation. In this short review, the advances in C–H bond activation reactions mediated or initiated by in situ amidation are summarized and analyzed.1 Introduction2 In Situ Amidation in Aryl C–H Bond Activation3 In Situ Amidation in Alkyl C–H Bond Activation4 Annulation Reactions via Amidation-Mediated C–H Activation5 Remote C–H Activation Mediated by Amidation6 Conclusion

A Review on Sulfur-Directed C−H Bond Activation

2020 ◽  
Vol 17 ◽  
Author(s):  
Xuchong Tang ◽  
Yingwei Zhao
Keyword(s):  
Transition Metal ◽  
Electron Donor ◽  
Bond Activation ◽  
Bond Formation ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Directing Group ◽  
Metal Catalyzed ◽  
Sulfur Containing

: Transition-metal-catalyzed C−H bond activation employing a directing group is becoming a powerful tool to access C−C or C−hetero bond formation. Oxygen and nitrogen atoms are commonly applied as the electron donor for these directing groups. In contrast, there are only few studies on sulfur-containing groups, probably due to their toxicity to transition-metal catalysts. Nowadays a large amount of C−H activation reactions directed by sulfur-containing auxiliary groups have been successfully achieved. Because these groups can be facilely removed or modified in situ or in further steps, they are of great value in creative synthetic strategies. This paper reviews recent advances in the studies using thioether, thiol/thiophenol/disulfide, sulfoxide, and thiocarbonyl as directing groups for intermolecular C−H functionalizations as well as intramolecular oxidative annulations.

Article

1999 ◽  
Vol 77 (7) ◽  
pp. 1225-1229 ◽  
Author(s):  
Pierre Dabo ◽  
André Cyr ◽  
Jean Lessard ◽  
Louis Brossard ◽  
Hugues Ménard
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Raney Nickel ◽  
Activated Charcoal ◽  
Vitreous Carbon ◽  
Electrocatalytic Hydrogenation ◽  
Reticulated Vitreous Carbon ◽  
Nickel Boride

Electrodes consisting of particles of a transition metal entrapped and dispersed in a reticulated vitreous carbon (RVC) matrix were prepared in situ by stirring the particles in the presence of an RVC cathode. Such electrodes were used for the electrocatalytic hydrogenolysis (ECHsis) of 4-phenoxyphenol, a compound representative of the 4-O-5 type linkage in lignins. The electrolyses were carried out under galvanostatic control in aqueous 1 M NaOH. Raney nickel, nickel boride, and transition metals supported on activated charcoal or alumina were used as catalytic powders. The extent and efficiency of the ECHsis of 4-phenoxyphenol was found to depend on the catalyst and on the temperature.Key words: electrocatalytic hydrogenation, electrocatalytic hydrogenolysis, 4-phenoxyphenol, Raney nickel, palladium on charcoal, palladium on alumina.

Chain-walking reactions of transition metals for remote C–H bond functionalization of olefinic substrates

2021 ◽  
Author(s):  
Soumen Ghosh ◽  
Sandeep Patel ◽  
Indranil Chatterjee
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Bond Activation ◽  
Feature Article ◽  
Bond Functionalization ◽  
A Chain ◽  
Chain Walking

Transition metal-assisted remote C–H bond activation at the non-classical reaction sites of various olefinic substrates with the aid of a chain-walking process is depicted in this feature article.

Methane activation by ZSM-5-supported transition metal centers

2021 ◽  
Author(s):  
Daniyal Kiani ◽  
Sagar Sourav ◽  
Yadan Tang ◽  
Jonas Baltrusaitis ◽  
Israel E. Wachs
Keyword(s):  
Transition Metal ◽  
Methane Activation ◽  
Group V ◽  
Metal Centers ◽  
Methane Dehydroaromatization

The literature on methane dehydroaromatization (MDA) to benzene using ZSM-5 supported, group V–VIII transition metal-based catalysts (MOx/ZSM-5) is critically reviewed with a focus on in situ and operando molecular insights.

Intercalation of First Row Transition Metals inside Covalent-Organic Frameworks (COF): a Strategy to Fine Tune the Electronic Properties of Porous Crystalline Materials

2018 ◽  
Author(s):  
Srimanta Pakhira ◽  
Jose Mendoza-Cortes
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Electronic Properties ◽  
High Surface ◽  
Electronic Devices ◽  
High Surface Area ◽  
Main Role ◽  
Covalent Organic Frameworks ◽  
Porous Network ◽  
Crystalline Materials

<div>Covalent organic frameworks (COFs) have emerged as an important class of nano-porous crystalline materials with many potential applications. They are intriguing platforms for the design of porous skeletons with special functionality at the molecular level. However, despite their extraordinary properties, it is difficult to control their electronic properties, thus hindering the potential implementation in electronic devices. A new form of nanoporous material, COFs intercalated with first row transition metal is proposed to address this fundamental drawback - the lack of electronic tunability. Using first-principles calculations, we have designed 31 new COF materials <i>in-silico</i> by intercalating all of the first row transition metals (TMs) with boroxine-linked and triazine-linked COFs: COF-TM-x (where TM=Sc-Zn and x=3-5). This is a significant addition considering that only 187 experimentally COFs structures has been reported and characterized so far. We have investigated their structure and electronic properties. Specifically, we predict that COF's band gap and density of states (DOSs) can be controlled by intercalating first row transition metal atoms (TM: Sc - Zn) and fine tuned by the concentration of TMs. We also found that the $d$-subshell electron density of the TMs plays the main role in determining the electronic properties of the COFs. Thus intercalated-COFs provide a new strategy to control the electronic properties of materials within a porous network. This work opens up new avenues for the design of TM-intercalated materials with promising future applications in nanoporous electronic devices, where a high surface area coupled with fine-tuned electronic properties are desired.</div>

Carbon Dioxide-Mediated C(sp2)–H Arylation of Primary and Secondary Benzylamines

2018 ◽  
Author(s):  
Mohit Kapoor ◽  
Pratibha Chand-Thakuri ◽  
Michael Young
Keyword(s):  
Carbon Dioxide ◽  
Transition Metal ◽  
Bond Activation ◽  
Bond Formation ◽  
Carbon Bond ◽  
Chelate Effect ◽  
Free Amine ◽  
Carbon Carbon Bond ◽  
New Strategy ◽  
Metal Catalyzed

Carbon-carbon bond formation by transition metal-catalyzed C–H activation has become an important strategy to fabricate new bonds in a rapid fashion. Despite the pharmacological importance of <i>ortho</i>-arylbenzylamines, however, effective <i>ortho</i>-C–C bond formation from C–H bond activation of free primary and secondary benzylamines using Pd<sup>II</sup> remains an outstanding challenge. Presented herein is a new strategy for constructing <i>ortho</i>-arylated primary and secondary benzylamines mediated by carbon dioxide (CO<sub>2</sub>). The use of CO<sub>2</sub> is critical to allowing this transformation to proceed under milder conditions than previously reported, and that are necessary to furnish free amine products that can be directly used or elaborated without the need for deprotection. In cases where diarylation is possible, a chelate effect is demonstrated to facilitate selective monoarylation.

Bond-length distributions for ions bonded to oxygen: Metalloids and post-transition metals

2017 ◽  
Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Metal Ions ◽  
Bond Length ◽  
Lone Pair ◽  
Transition Metal Ions ◽  
Oxygen Lone Pair

Bond-length distributions are examined for thirty-three configurations of the metalloid ions and fifty-six configurations of the post-transition-metal ions bonded to oxygen. Lone-pair stereoactivity is discussed.

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