Selective CF Bond Activation of Tetrafluorobenzenes by Nickel(0) with a Nitrogen Donor Analogous to N-Heterocyclic Carbenes

2009 ◽  
Vol 48 (12) ◽  
pp. 2185-2187 ◽  
Author(s):  
Meghan E. Doster ◽  
Samuel A. Johnson
Keyword(s):  
Bond Activation ◽  
Heterocyclic Carbenes ◽  
Nitrogen Donor

Novel Intramolecular CAryl–S Bond Activation by an Electron Rich, Ring-Expanded-NHC-Rh centre: A Combined Experimental and DFT Study

2011 ◽  
Vol 64 (8) ◽  
pp. 1141 ◽  
Author(s):  
Abeer Binobaid ◽  
Kingsley J. Cavell ◽  
Mikhail S. Nechaev ◽  
Benson M. Kariuki
Keyword(s):  
Bond Activation ◽  
Reaction Pathway ◽  
Heterocyclic Carbenes ◽  
Dft Study ◽  
Dft Studies ◽  
X Ray ◽  
Carbene Complex ◽  
Donor Capacity ◽  
Insight Into ◽  
Sulfur Bond

The reaction of (o-MeSPh)-N-functionalized tetrahydropyrimidinium salts with KN(SiMe3)2 and [Rh(COD)Cl]2 in THF leads to the formation of a novel dimeric RhIII bis-carbene complex. The reaction involves the unexpected cleavage/oxidative addition of the aryl-sulfur bond to give dimeric metallated RhIII with bridging MeS< moieties. This unusual reaction is probably a consequence of the sterically imposing structure and strong donor capacity of ring-expanded N-heterocyclic carbenes (RE-NHCs). An X-ray structure of the [(Ph,DIPP-NHC)Rh(Cl)(SMe)2] product complex has been obtained, and DFT studies were undertaken to gain an insight into the reaction pathway.

Activation of C–F, Si–F, and S–F Bonds by N-Heterocyclic Carbenes and Their Isoelectronic Analogues

Synlett ◽  
2020 ◽  
Vol 31 (14) ◽  
pp. 1349-1360 ◽  
Author(s):  
Eunsung Lee ◽  
Ewa Pietrasiak
Keyword(s):  
Nucleophilic Substitution ◽  
Organic Synthesis ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Oxidative Addition ◽  
Main Group ◽  
Heterocyclic Carbenes ◽  
Full Potential ◽  
Short Summary ◽  
Special Case

Reactions involving C–F, Si–F, and S–F bond cleavage with N-heterocyclic carbenes and isoelectronic species are reviewed. Most examples involve activation of aromatic C–F bond via an SNAr pathway and nucleophilic substitution of fluorine in electron-deficient olefins. The mechanism of the C–F bond activation depends on the reaction partners and the reaction can proceed via addition–elimination, oxidative addition (concerted or stepwise) or metathesis. The adducts formed upon substitution find applications in organic synthesis, as ligands and as stable radical precursors, but in most cases, their full potential remains unexplored.1 Introduction1.1 The C–F Bond1.2 C–F Bond Activation: A Short Summary1.3 C–F Bond Activation: A Special Case of SNAr1.4 N-Heterocyclic Carbenes (NHCs)1.5 The Purpose of this Article2 C–F bond Activation in Acyl Fluorides3 Activation of Vinylic C–F Bonds4 Activation of Aromatic C–F Bonds5 X–F Bond Activation (X = S or Si)6 C–F Bond Activation by Main Group Compounds Isoelectronic with NHCs7 Conclusions and Outlook

scholarly journals Abnormal N-heterocyclic Carbenes: More than Just Exceptionally Strong Donor Ligands

2011 ◽  
Vol 64 (8) ◽  
pp. 1113 ◽  
Author(s):  
Anneke Krüger ◽  
Martin Albrecht
Keyword(s):  
Water Oxidation ◽  
Bond Activation ◽  
Heterocyclic Carbenes ◽  
Oxidation Catalysis ◽  
Donor Ligands ◽  
Free Alcohol ◽  
Carbene Ligands ◽  
Transfer Processes ◽  
Oxidative Transformations ◽  
Electron Transfer Processes

Complexes comprising a so-called abnormal carbene ligand, which displays pronounced mesoionic character, have recently been shown to be competent catalyst precursors for bond activation processes and oxidative transformations, including base-free alcohol oxidation and water oxidation. In this highlight we propose that these abnormal carbene ligands are not just useful spectator ligands but also actively participate in the bond activation step. This mode of action is partially based on the exceptionally strong donor properties of the ligand and, specifically, on the mesoionic character of these abnormal carbenes. The mesoionic properties provide a reservoir for charges and holes and thus induce efficient ligand-metal cooperativity, which is beneficial in particular for oxidation catalysis that involves concerted proton and electron transfer processes.

Intramolecular CN Bond Activation and Ring-Expansion Reactions of N-Heterocyclic Carbenes

2014 ◽  
Vol 21 (4) ◽  
pp. 1434-1438 ◽  
Author(s):  
Patrick Hemberger ◽  
Andras Bodi ◽  
Johannes H. J. Berthel ◽  
Udo Radius
Keyword(s):  
Bond Activation ◽  
Ring Expansion ◽  
Heterocyclic Carbenes

Tuning N-Heterocyclic Carbenes in T-Shaped PtII Complexes for Intermolecular CH Bond Activation of Arenes

2012 ◽  
Vol 124 (16) ◽  
pp. 4002-4005 ◽  
Author(s):  
Orestes Rivada-Wheelaghan ◽  
Manuel A. Ortuño ◽  
Josefina Díez ◽  
Agustí Lledós ◽  
Salvador Conejero
Keyword(s):  
Bond Activation ◽  
Heterocyclic Carbenes

Coordination, Agostic Stabilization, and C−H Bond Activation of N-Alkyl Heterocyclic Carbenes by Coordinatively Unsaturated Ruthenium Hydride Chloride Complexes

2009 ◽  
Vol 28 (23) ◽  
pp. 6676-6686 ◽  
Author(s):  
Suzanne Burling ◽  
Elena Mas-Marzá ◽  
José E. V. Valpuesta ◽  
Mary F. Mahon ◽  
Michael K. Whittlesey
Keyword(s):  
Bond Activation ◽  
Heterocyclic Carbenes ◽  
Chloride Complexes ◽  
Ruthenium Hydride
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