A convenient and efficient C–OH bond activation, PdCl2(PPh3)2catalyzed, C–C bond formation of tautomerizable quinolinones with the aid of BOP reagent and boronic acids

RSC Advances ◽  
2014 ◽  
Vol 4 (76) ◽  
pp. 40259-40268 ◽  
Author(s):  
Yadavalli Suneel Kumar ◽  
C. Dasaradhan ◽  
Kamalakannan Prabakaran ◽  
Fazlur-Rahman Nawaz Khan ◽  
Euh Duck Jeong ◽  
...  
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Boronic Acids

C–C bond formation of tautomerizable quinolinones. C–OH bond activation using BOP reagent and boronic acids.

ChemInform Abstract: A Convenient and Efficient C-OH Bond Activation, PdCl2(PPh3)2Catalyzed, C-C Bond Formation of Tautomerizable Quinolinones with the Aid of BOP Reagent and Boronic Acids

ChemInform ◽  
2015 ◽  
Vol 46 (12) ◽  
pp. no-no
Author(s):  
Yadavalli Suneel Kumar ◽  
C. Dasaradhan ◽  
Kamalakannan Prabakaran ◽  
Fazlur-Rahman Nawaz Khan ◽  
Euh Duck Jeong ◽  
...  
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Boronic Acids

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.

scholarly journals Rate Dependence on Inductive and Resonance Effects for the Organocatalyzed Enantioselective Conjugate Addition of Alkenyl and Alkynyl Boronic Acids to β-Indolyl Enones and β-Pyrrolyl Enones

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1615
Author(s):  
Amy Boylan ◽  
Thien S. Nguyen ◽  
Brian J. Lundy ◽  
Jian-Yuan Li ◽  
Ravikrishna Vallakati ◽  
...  
Keyword(s):  
Positive Charge ◽  
Bond Formation ◽  
Conjugate Addition ◽  
Reaction Rates ◽  
Boronic Acids ◽  
Key Factors ◽  
Resonance Contribution ◽  
Reaction Conditions ◽  
Resonance Effects ◽  
Resonance Stabilization

Two key factors bear on reaction rates for the conjugate addition of alkenyl boronic acids to heteroaryl-appended enones: the proximity of inductively electron-withdrawing heteroatoms to the site of bond formation and the resonance contribution of available heteroatom lone pairs to stabilize the developing positive charge at the enone β-position. For the former, the closer the heteroatom is to the enone β-carbon, the faster the reaction. For the latter, greater resonance stabilization of the benzylic cationic charge accelerates the reaction. Thus, reaction rates are increased by the closer proximity of inductive electron-withdrawing elements, but if resonance effects are involved, then increased rates are observed with electron-donating ability. Evidence for these trends in isomeric substrates is presented, and the application of these insights has allowed for reaction conditions that provide improved reactivity with previously problematic substrates.

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

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

ChemInform Abstract: C-C Bond Formation via C-H Bond Activation under Protic Conditions: The Role of Phosphane Ligand and Cosolvent.

ChemInform ◽  
2010 ◽  
Vol 41 (18) ◽  
Author(s):  
Marc-Olivier Simon ◽  
Remi Martinez ◽  
Jean-Pierre Genet ◽  
Sylvain Darses
Keyword(s):  
Bond Activation ◽  
Bond Formation

ChemInform Abstract: C-C Bond Formation via C-H Bond Activation Using an in situ Generated Ruthenium Catalyst.

ChemInform ◽  
2009 ◽  
Vol 40 (44) ◽  
Author(s):  
Remi Martinez ◽  
Marc-Olivier Simon ◽  
Reynald Chevalier ◽  
Cyrielle Pautigny ◽  
Jean-Pierre Genet ◽  
...  
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Ruthenium Catalyst
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