8 results match your criteria: "Center of Bio-Medical Research[Affiliation]"

Metal-catalysed C-H bond activation and borylation.

Chem Soc Rev

June 2022

Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India.

Article Synopsis
  • The direct borylation of hydrocarbons via C-H bond activation has gained popularity due to the versatility of organoboron compounds, though controlling site-selectivity has been a key challenge.
  • Significant progress has been made in improving selectivity for both proximal and distal C-H bond borylation through innovative methodologies, including new catalytic systems and modifications to directing groups.
  • This review article outlines various approaches, advancements in aliphatic C(sp)-H and enantioselective borylations, and highlights the applications of C-H borylation in natural product synthesis, therapeutics, and materials chemistry since 2014.
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Remarkably Efficient Iridium Catalysts for Directed C(sp)-H and C(sp)-H Borylation of Diverse Classes of Substrates.

J Am Chem Soc

April 2021

Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow, 226014 Uttar Pradesh, India.

Article Synopsis
  • This study introduces a new class of C-H borylation catalysts that use Ir-C(thienyl) or Ir-C(furyl) anionic ligands for regioselective borylation of various aromatic and aliphatic compounds.
  • The catalysts demonstrate strong reactivity and selectivity, achieving high yields in borylation reactions, including challenging heterocycles and late-stage functionalizations.
  • Notably, one catalyst can operate in open air, expanding the method's versatility, and initial mechanistic insights suggest that the Ir(bis)boryl complex is the key active species.
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Iron-Catalyzed Amination of Strong Aliphatic C(sp)-H Bonds.

J Am Chem Soc

September 2020

Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India.

A concept for intramolecular denitrogenative C(sp)-H amination of 1,2,3,4-tetrazoles bearing unactivated primary, secondary, and tertiary C-H bonds is discovered. This catalytic amination follows an unprecedented metalloradical activation mechanism. The utility of the method is showcased with the short synthesis of a bioactive molecule.

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Double-Fold Ortho and Remote C-H Bond Activation/Borylation of BINOL: A Unified Strategy for Arylation of BINOL.

Org Lett

August 2019

Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery , SGPGIMS Campus, Raebareli Road , Lucknow 226014 , Uttar Pradesh , India.

A double-fold ortho and remote C-H borylation of BINOL is described. The proposed mechanisms involved electrostatically and sterically directed ortho and remote C-H activation processes, respectively. While Beg (eg = ethylene glycolate) directs the C-H activation at ortho positions, a combination of HBpin and Bpin activates remote C-H bonds.

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Ir-Catalyzed Intramolecular Transannulation/C(sp)-H Amination of 1,2,3,4-Tetrazoles by Electrocyclization.

J Am Chem Soc

July 2018

Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery , SGPGIMS Campus , Raebareli Road , Lucknow 226014 , Uttar Pradesh , India.

An efficient strategy for the intramolecular denitrogenative transannulation/C(sp)-H amination of 1,2,3,4-tetrazoles bearing C8-substituted arenes, heteroarenes, and alkenes is described. The process involves the generation of the metal-nitrene intermediate from tetrazole by the combination of [Cp*IrCl] and AgSbF. It has been shown that the reaction proceeds via an unprecedented electrocyclization process.

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Noncovalent Interactions in Ir-Catalyzed C-H Activation: L-Shaped Ligand for Para-Selective Borylation of Aromatic Esters.

J Am Chem Soc

June 2017

Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus , Raebareli Road, Lucknow 226014, Uttar Pradesh, India.

An efficient strategy for the para-selective borylation of aromatic esters is described. For achieving high para-selectivity, a new catalytic system has been developed modifying the core structure of the bipyridine. It has been proposed that the L-shaped ligand is essential to recognize the functionality of the oxygen atom of the ester carbonyl group via noncovalent interaction, which provides an unprecedented controlling factor for para-selective C-H activation/borylation.

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A strategy for affecting ortho versus meta/para selectivity in Ir-catalyzed C-H borylations (CHBs) of phenols is described. From selectivity observations with ArylOBpin (pin = pinacolate), it is hypothesized that an electrostatic interaction between the partial negatively charged OBpin group and the partial positively charged bipyridine ligand of the catalyst favors ortho selectivity. Experimental and computational studies designed to test this hypothesis support it.

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Formal Ir-Catalyzed Ligand-Enabled Ortho and Meta Borylation of Aromatic Aldehydes via in Situ-Generated Imines.

J Am Chem Soc

January 2016

Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareli Road, Lucknow, Uttar Pradesh 226014, India.

The ligand-enabled development of ortho and meta C-H borylation of aromatic aldehydes is reported. It was envisaged that while ortho borylation could be achieved using tert-butylamine as the traceless protecting/directing group, meta borylation proceeds via an electrostatic interaction and a secondary interaction between the ligand of the catalyst and the substrate. These ligand-substrate electrostatic interactions and secondary B-N interactions provide an unprecedented controlling factor for meta-selective C-H activation/borylation.

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