Transition metal complexes bearing NHC ligands substituted with secondary polyfluoroalkyl groups

Abstract

Using three different approaches, racemic 1-(perfluoroalkyl)ethylamines were synthesized from perfluoroalkyl iodides or perfluoroalkanoic acids, and further transformed to the corresponding N,N'-disubstituted ethane-1,2-diimines and ethane-1,2-diamines as mixtures of diastereoisomers. Their cyclization afforded imidazolium or dihydroimidazolium salts, which led to silver or palladium complexes bearing NHC ligands substituted with secondary polyfluoroalkyl groups. The palladium complexes bearing a throwaway 3-chloropyridine ligand proved to be moderately active in the model Suzuki-Miyaura coupling.

2-Iodoxybenzoic acid ditriflate: the most powerful hypervalent iodine(v) oxidant

“…It should be emphasized that previously known procedures for preparation of polyfluoroaldehydes (in the form of gem-diols) are based on the reduction of corresponding polyfluorocarboxylic acids or other indirect methods. [23][24][25][26][27][28][29] Polyfluoroaldehydes represent a practically important class of organofluorine compounds; 30 however, to the best of our knowledge, their preparation by direct oxidation of readily available polyfluorinated primary alcohols was not previously reported in the literature. In conclusion, we have reported the preparation of new powerful hypervalent iodine(V) oxidant, ditriflate derivative of 2-iodoxybenzoic acid (IBX-ditriflate 4), by the reaction of IBX with triflic acid.…”

Synthesis, characterization, crystal structure, α‐glycosidase, and acetylcholinesterase inhibitory properties of 1,3‐disubstituted benzimidazolium salts

“…Additionally, fluorinated NHC ligands and their complexes with different metals have been studied in recent decades. [38][39][40][41][42][43][44] Some of the published works in the literature prove that these transition metal complexes containing fluorinated NHC ligand are easy to prepare, require no special handling precautions, and are quite good catalysts in many organic reactions (e.g., hydrosilylation of propargylic alcohols, Mizoroki-Heck arylations, and transfer hydrogenations) giving high yields. [45][46][47][48] These complexes containing fluorinated NHC ligand also possess good biological activities.…”

Medium Fluorous Separation Using Hydrofluoroether and Weakly Polar Solvents for Environmentally Friendly Recycling of Catalysts

“…Both procedures required column chromatography separation. In continuation of our search for new medium or heavy fluorous PEPPSI catalyst analogues, 34,35 we synthesized analogous fluorous pyridine 3 containing two shorter perfluorohexyl groups by Negishi coupling in 35% yield without the need of chromatography by medium fluorous separation using a HFE 7500/1,2-dichloroethane solvent mixture (Scheme 2).…”

“…However, they are also the most difficult, because the attachment of the NHC ligands requires sufficient stability of the corresponding free carbene. Thus, NHC ligands bearing linear 33,34 or branched 35 aliphatic polyfluorinated chains could be employed for the synthesis of Ag or Pd complexes, but their attachment to Ru complexes failed. 1,3-Dimesityl-imidazolidinylidene ligand thus emerged as the optimal target for fluorous derivatization.…”