Fluorinated isocyanides

In fluorinated isocyanide dihalides and imidoyl halides the halogens are replaeed by alkoxyls [19 20, 21] (equation 18)... 

Lentz, D. (1994) Fluorinated isocyanides-more than ligands with unusual properties. Angew. Chem. Int. Ed. Engl, 33,1315-31. 

The first fluorinated isocyanide, trifluormethyl isocyanide, was synthesized by Makarov et al. (5). Its chemistry, however, remained unexplored until a high yield... 

Isocyanides react with fluorine [75 to yield difluoromethylene imines, which tend to dimerize In an inert solvent, imines accept fluorine fioin trifluoromethyl hypofluorite [76, 77] (equation 11)... 

Lateral monofluorination of the p-alkoxyphenyl isocyanide system [XAu (CNC6H40C H2 +i)] (X = C1, Br, I), in ortho-(3-F) (6a) and meta-(2-F) (6b) positions relative to the alkoxy chain was also studied [18]. None of the free fluorinated ligands is a LC, but their gold complexes display mesomorphic properties. This is a typical case of a promesogenic ligand which yields a mesogen upon coordination to a metal. 

In studying the reactivity of iV-fluoropyridinium fluoride 127 obtained from pyridine 126 by treatment with fluorine gas in chloroform at low temperature (Scheme 30), Kiselyov studied reactions with isocyanides in the presence of trimethylsilylazide <2005TL4851>. A mixture of products was obtained in which, besides tetrazolylpyr-idine 128 and a nicotinamide derivative 129 also tetrazolo[l,5-tf]pyridine 1 was obtained in very poor yield (5-10%). 

Dichlorocarbene reacts exothermically under soliddiquid two-phase conditions with azides to produce, initially, isocyanide dichlorides, RN=CC12, which can react further to give A-alkyltetrachloroaziridines [50], The aziridines are the major products (60-70%) with simple alkyl azides, but the reaction tends to stop at the isocyanide step (50-60%), when the alkyl group is highly fluorinated. 

The utility of TOSMIC in MCR reactions has also received recent interest in the pharmaceutical arena as an approach to the preparation of imidazoles 91. Originally reported by van Leusen in 1977 [76], and involving cycloaddition of tosyl-methyl isocyanides to carbon-nitrogen double bonds, recent elegant work by Sisko et al. has heightened its profile with the description of a one-pot synthesis of imidazole 92, a potent inhibitor of p38 MAP kinase, implicated with the release of the pro-inflammatory cytokine TNF-a (Scheme 11.19) [77]. In this particular example a fluorinated analogue of TOSMIC 90, is employed. 

Figure 2.40 Euminescent fluorinated crown-ether-isocyanide gold(I) metallo-mesogens...

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