Palladium(II)-Catalyzed C–H Bond Activation/C–C and C–O Bond Formation Reaction Cascade: Direct Synthesis of Coumestans

2016 ◽  
Vol 81 (23) ◽  
pp. 11971-11977 ◽  
Author(s):  
Kashmiri Neog ◽  
Ashwini Borah ◽  
Pranjal Gogoi
Keyword(s):  
Bond Activation ◽  
Direct Synthesis ◽  
Bond Formation ◽  
Formation Reaction

Synthesis of Benzamide Derivatives by the Reaction of Arenes and Isocyanides through a C–H Bond Activation Strategy

Synlett ◽  
2017 ◽  
Vol 29 (01) ◽  
pp. 94-98 ◽  
Author(s):  
Mehdi Khalaj ◽  
Mahboubeh Taherkhani ◽  
Seyed Mousavi-Safavi ◽  
Jafar Akbari
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Benzene Derivatives ◽  
Formation Reaction ◽  
Cross Coupling Reactions ◽  
Carbon Carbon Bond ◽  
Benzamide Derivatives

A carbon–carbon bond formation reaction between isocyanides and benzene derivatives is reported. In contrast to traditional cross-coupling reactions, which require aryl halides or pseudohalides, we use a palladium catalyst to generate the aryl–palladium through C–H bond activation of arenes. This method offers an attractive approach to a range of benzamides from readily accessible benzene derivatives.

Imine as a Linchpin Approach for Distal C(sp2)–H Functionalization

2020 ◽  
Author(s):  
Sukdev Bag ◽  
Sadhan Jana ◽  
Sukumar Pradhan ◽  
Suman Bhowmick ◽  
Nupur Goswami ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Bond Activation ◽  
Bond Formation ◽  
Ancillary Ligand ◽  
Significant Challenge ◽  
Site Selectivity ◽  
Directing Group ◽  
Covalently Linked ◽  
Complex Organic ◽  
Post Functionalization

<p>Despite the widespread applications of C–H functionalization, controlling site selectivity remains a significant challenge. Covalently attached directing group (DG) served as an ancillary ligand to ensure proximal <i>ortho</i>-, distal <i>meta</i>- and <i>para</i>-C-H functionalization over the last two decades. These covalently linked DGs necessitate two extra steps for a single C–H functionalization: introduction of DG prior to C–H activation and removal of DG post-functionalization. We introduce here a transient directing group for distal C(<i>sp<sup>2</sup></i>)-H functionalization <i>via</i> reversible imine formation. By overruling facile proximal C-H bond activation by imine-<i>N</i> atom, a suitably designed pyrimidine-based transient directing group (TDG) successfully delivered selective distal C-C bond formation. Application of this transient directing group strategy for streamlining the synthesis of complex organic molecules without any necessary pre-functionalization at the distal position has been explored.</p>

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.

Sunlight-induced C C bond formation reaction: Radical addition of alcohols/ethers/acetals to olefins

2021 ◽  
Vol 413 ◽  
pp. 113263
Author(s):  
Mamiko Hayakawa ◽  
Hisashi Shirota ◽  
Souta Hirayama ◽  
Ryuusei Yamada ◽  
Tadashi Aoyama ◽  
...  
Keyword(s):  
Bond Formation ◽  
Radical Addition ◽  
Formation Reaction

Peptide Modifications: Versatile Tools in Peptide and Natural Product Syntheses

Synlett ◽  
2019 ◽  
Vol 30 (11) ◽  
pp. 1289-1302 ◽  
Author(s):  
Phil Servatius ◽  
Lukas Junk ◽  
Uli Kazmaier
Keyword(s):  
Amino Acids ◽  
Natural Product ◽  
Bond Activation ◽  
Bond Formation ◽  
Side Chain ◽  
Peptide Backbone ◽  
Claisen Rearrangements ◽  
The Past ◽  
Allylic Alkylations ◽  
Peptide Modifications

Peptide modifications via C–C bond formation have emerged as valuable tools for the preparation and alteration of non-proteinogenic amino acids and the corresponding peptides. Modification of glycine subunits in peptides allows for the incorporation of unusual side chains, often in a highly stereoselective manner, orchestrated by the chiral peptide backbone. Moreover, modifications of peptides are not limited to the peptidic backbone. Many side-chain modifications, not only by variation of existing functional groups, but also by C–H functionalization, have been developed over the past decade. This account highlights the synthetic contributions made by our group and others to the field of peptide modifications and their application in natural product syntheses.1 Introduction2 Peptide Backbone Modifications via Peptide Enolates2.1 Chelate Enolate Claisen Rearrangements2.2 Allylic Alkylations2.3 Miscellaneous Modifications3 Side-Chain Modifications3.1 C–H Activation3.1.1 Functionalization via Csp3–H Bond Activation3.2.2 Functionalization via Csp2–H Bond Activation3.2 On Peptide Tryptophan Syntheses4 Conclusion

Cu-catalyzed C–H Activation Reaction: One Pot Direct Synthesis of Xanthine and Uric Acid Derivatives from 5-Bromo Uracil

Synlett ◽  
2021 ◽  
Author(s):  
Habibur Rahaman ◽  
Brindaban Roy ◽  
Somjit Hazra ◽  
Biplab Mondal
Keyword(s):  
Uric Acid ◽  
Bond Activation ◽  
Direct Synthesis ◽  
One Pot ◽  
Activation Reaction

Abstract: A one pot direct synthesis of xanthine and uric acid derivates is reported. This simple yet efficient methodology illustrates concurrent formation of two C-N bonds using CuBr2 as catalyst and one of those C-N bonds is formed by uracil C6-H bond activation.

Pd(ii)-Catalyzed oxidative alkenylation of 4-hydroxycoumarin with maleimide via a C–H bond activation strategy

2021 ◽  
Author(s):  
Kumud Sharma ◽  
Kashmiri Neog ◽  
Abhilash Sharma ◽  
Pranjal Gogoi
Keyword(s):  
Bond Activation ◽  
Direct Synthesis

A Pd(ii)-catalyzed oxidative alkenylation of 4-hydroxycoumarins with maleimides has been developed for the direct synthesis of novel 4-hydroxy-3-maleimidecoumarins without prefunctionalization.

Recent Innovative Strategies for the Synthesis of Amines: From CN Bond Formation to CN Bond Activation

ChemSusChem ◽  
2009 ◽  
Vol 2 (8) ◽  
pp. 715-717 ◽  
Author(s):  
Karolin Krüger ◽  
Annegret Tillack ◽  
Matthias Beller
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Innovative Strategies
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