Bifunctional N‐Heterocyclic Carbene Ferrocenyl Ligands – Synthesis and Palladium(II) Complexes

Abstract

Two ferrocenylimidazolium tetrafluoroborate salts [R = Me, 7 and R = (2,4,6-trimethylphenyl), 8], precursors of new ferrocenylimidazol-2-ylidene bifunctional ligands, have been prepared for the first time. The free 1-(2-dimethylaminomethyl)ferrocenyl-3-methylimidazol-2-ylidene (12) was isolated and characterised by 1 H and 13 C NMR spectroscopy and repre-[a]

Cobalt‐Catalyzed ortho‐Methylation of Ferrocenes Bearing ortho‐Directing Groups by Catalytic Directed C–H Bond Activation

“…[70] Our attempts towards a cobalt-catalyzed methylation afforded rac-16 in 35 % yield (Scheme 5). [71] Some other ODGs showed no reactivity under the applied reaction conditions, as compounds 17, [72] 18, [73] and 19 were completely re-isolated (Scheme 6). The molecule adopts a conformation with almost coplanarity (dihedral angle -8.0°) of the aminocarbonyl group, the methyl-substituted cyclopentadienyl ligand with the oxygen atom directed to the methyl group (syn conformation), and a distance between the oxygen atom and the methyl carbon atom of 297.8 pm.…”

“…Scheme 5. . [71] Some other ODGs showed no reactivity under the applied reaction conditions, as compounds 17, [72] 18, [73] and 19 were completely re-isolated (Scheme 6). The diisopropyl(pyridyl)silyl ODG has been introduced by Grevorgyan, who successfully applied it in palladium-catalyzed ortho-functionalizations of arenes.…”

Haloferrocenes: Syntheses and Selected Reactions

“…The reaction took place in DMSO at 90 °C in the presence of copper(I) iodide and a base such as potassium carbonate or potassium tert-butoxide, and afforded products such as 87 or 88 in up to 84% yield (Scheme 29). 60 Related reactions were performed by Bolm et al, 60 Nagarkar et al, 61 Jiang et al 62 as well as by Labande et al 63 with imidazole in the context of the generation of heterocyclic carbenes.…”

Planar‐Chiral Ferrocene‐Based N‐Heterocyclic Carbene Ligands

“…In 2015, Labande and colleagues reported PPFA‐type ligand ( rac )‐ 24 (Scheme ) . Whereas PPFA possesses both central and planar chirality (Figure ), 24 has only planar chirality.…”

“…In 2015, Labande and colleagues reported PPFA-type ligand (rac)-24 (Scheme 12). [34] Whereas PPFA possesses both central and planarc hirality (Figure 1 thyl)ferrocene 21,c arbene precursor[ 24H]BF 4 was prepared by introducing a1 -methylimidazolyl group into the ortho-position with respectt ot he dimethylamino group. The generation of free carbene 24 was confirmed by NMR experiments after deprotonation of [24H]BF 4 by using the strong base, KHMDS (potassium hexamethyldisilazide).P dc omplex [PdCl 2 (24-k 2 N,C)] was synthesized from [24H]BF 4 and [PdCl 2 (CH 3 CN) 2 ]i nt he presence of KOtBu.…”