Transition-metal catalysed C–N bond activation

2016 ◽  
Vol 45 (5) ◽  
pp. 1257-1272 ◽  
Author(s):  
Quanjun Wang ◽  
Yijin Su ◽  
Lixin Li ◽  
Hanmin Huang
Keyword(s):  
Transition Metal ◽  
Bond Activation ◽  
Bond Formation ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed ◽  
Bond Formation Reactions

Efficient strategies for transition-metal catalyzed C–N bond activation and their applications in new C–X bond formation reactions are summarized.

Developments in Organocatalyzed C(Ar)- C(Ar) Bond formation Reactions via Single Electron Transfer Mechanism: An Overview

2021 ◽  
Vol 08 ◽  
Author(s):  
Lalit Yadav ◽  
Sandeep Chaudhary
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Metal Free ◽  
Cross Coupling Reactions ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

: The formation of new bonds through C-C bond formation is of utmost importance in the synthesis of biologically privileged scaffolds and therapeutic drugs. In recent years, extensive efforts has been done to improve the intermolecular and intramolecular cross-coupling reaction in the simple, mild, efficient, economical, and eco-friendly manner via transition metal-free or organocatalytic direct C-H bond activation methodology. The traditional crosscoupling era continuously shifted to metal-free, organocatalytic, or metal-free cross-dehydrogenative coupling strategies to fast-track the reactions and diminishing the typical purification processes. Therefore, recent advances on the transitionmetal-free, organocatalytic inter- and intra-molecular cross-coupling reactions have been introduced and discussed in the present article. In view of the reaction mechanism, organocatalytic cross-coupling reactions undergo through the radical pathways, radical anionic intermediate which is completely different from traditional transition metal-catalyzed reactions. The exploration of transition metal-free organocatalyzed cross-couplings for direct C-H arylation of arenes has grown significantly, thereby, improving the formation of a wide range of aryl-aryl /aryl-heteroaryl/ heteroaryl-heteroaryl compounds. In the survey, transition metal-free/organocatalytic cross-coupling reactions showed a higher efficiency under simple and mild conditions than the comparative transition metal-catalyzed cross-coupling reactions. However, the higher regioselectivity and chemoselectivity are still far ahead in organocatalytic cross-coupling reactions due to their specific intrinsic mechanistic pathway. The tuning of many parameters such as oxidative states, ligands coordination, and counter anions, etc., which results in the specific direct C-H functionalization with flexible methodology are missing in the transition metal-free cross-coupling reactions. The highly systematic transition metal-catalyzed chemistry is still playing a dominant role over transition metal-free chemistry in organic synthesis. The organocatalyzed transition-metal-free conditions should be more efficient, chemoselective, and regioselective for further potential development and applications in organic synthesis. For the endless pursuit of sustainable chemistry and green chemistry, such transition-metalfree/organocatalytic reactions should be never ceased. Additional curious attention and interest have been developed so far, and chemists are showing their eagerness and talents to uncover the hidden treasure of green chemistry. In this review article, we highlighted the developments of various transition metal-free/organocatalytic C-H bond activation reactions which further encourages the advancement in the development of sustainable C-C coupling reactions and their further applications towards the synthesis of biologically privileged scaffolds and drug molecules.

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.

Transition-Metal-Catalyzed Oxidative and Decarboxylative Acylations through sp2 C-H Bond Activation

2015 ◽  
Vol 20 (5) ◽  
pp. 471-511 ◽  
Author(s):  
Satyasheel Sharma ◽  
Neeraj Kumar Mishra ◽  
Youngmi Shin ◽  
In Su Kim
Keyword(s):  
Transition Metal ◽  
Bond Activation ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed
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