Collect. Czech. Chem. Commun. 2008, 73, 1799-1813

HFPO Trimer-Based Alkyl Triflate, a Novel Building Block for Fluorous Chemistry. Preparation, Reactions and 19F gCOSY Analysis

Ondřej Kysilkaa, Markéta Rybáčkováa, Martin Skalickýa, Magdalena Kvíčalováb, Josef Cvačkac and Jaroslav Kvíčalaa,*

a Department of Organic Chemistry, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
b Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Husinec-Řež 1001, 250 68 Řež, Czech Republic
c Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám. 2, 166 10 Prague 6, Czech Republic


Triflate 4, CF3(CF2)2O-CF(CF3)CF2O-CF(CF3)CH2-OTf (RFOCH2OTf), of the HFPO trimer-based alcohol 3 (RFOCH2OH) is a novel highly fluorinated building block for fluorous chemistry. In analogy to similar polyfluorinated triflates with methylene spacer, its reactivity is limited to strong and soft nucleophiles. Whereas reactions with cyanide anion, phenolate anion, enolate of diethyl malonate or lithium salt of benzaldehyde bis(phenylsulfanyl)acetal were unsuccessful, the corresponding imidazole 5, iodide 6 or azide 7 were prepared in good yields. Reaction of imidazole 5 with (perfluorohexyl)methyl triflate (9) afforded highly fluorinated non-crystalline imidazolium salt 8, TfO-RFOCH2-(C3H3N2)+-CH2C6F13-n, which could be employed as fluorous ionic liquid or intermediate for fluorous carbenes. Complete assignment of complex 19F NMR spectra of all compounds employed was accomplished using 19F gCOSY NMR method.

Keywords: Fluorous ligands; Polyethers; Polyfluorinated compounds; HFPO trimer; Triflates; Building blocks; 19F COSY spectroscopy; Imidazolium salts.

References: 41 live references.