25700-14-5Relevant articles and documents
Alcohol-Induced C?N Bond Cleavage of Cyclometalated N-Heterocyclic Carbene Ligands with a Methylene-Linked Pendant Imidazolium Ring
Zhong, Wei,Fei, Zhaofu,Scopelliti, Rosario,Dyson, Paul J.
, p. 12138 - 12144 (2016)
Reaction of the pentamethylcyclopentadienyl rhodium iodide dimer [Cp*RhI2]2with 1,1′-diphenyl-3,3′-methylenediimidazolium diiodide in non-alcohol solvents, in the presence of base, led to the formation of bis-carbene complex [Cp*Rh(bis-NHC)I]I (bis-NHC=1,1′-diphenyl-4,4′-methylenediimidazoline-5,5′-diylidene). In contrast, when employing alcohols as the solvent in the same reaction, cleavage of a methylene C?N bond is observed, affording ether-functionalized (cyclometalated) carbene ligands coordinated to the metal center and the concomitant formation of complexes with a coordinated imidazole ligand. Studies employing other 1,1′-diimidazolium salts indicate that the cyclometalation step is a prerequisite for the activation/scission of the C?N bond and, based on additional experimental data, a SN2 mechanism for the reaction is tentatively proposed.
A highly regioselective reaction of N-fluoropyridinium salts with stabilized sulfur, oxygen, and nitrogen nucleophiles: A convenient route to 2-substituted pyridines
Kiselyov,Strekowski
, p. 1361 - 1364 (2007/10/02)
2-Substituted pyridines are efficiently obtained by the reactions of N- fluoropyridinium tetrafluoroborate or triflate with anions derived from benzenethiols, phenols, azoles, cyanamide, and with azide anion. The results are consistent with a nucleophile addition at the position 2 of the N- fluoropyridinium cation as the major reaction pathway.
