Perfluoroalkyl copper complexes

Perfluoroalkyl)-5 -deoxy-5 -fluoro- and 5-(perfluoroalkyl)-2, 5 -di-deoxy-5 -fluoro-uridines were prepared " from 840 and 834, respectively, using perfluoroalkyl-copper complexes. Among them, 5 -deoxy-5 -fluoro-(846) and 2, 5 -dideoxy-5 -fluoro-5-(perfluoroethyl)uridine (839) were particularly effective against Ehrlich ascites carcinoma. 5-Hydroxyl (847) and 5-amino or 5-alkylamino (5-NHMe, -NHBu, -NHCH2Ph, -morpholino, -piperidino, and -pyrrolo) analogs (848) of 840 were prepared. The a anomer of 5 -deoxy-5 -fluorouridine (840) was also synthesized. "... 

The mechanism of the copper-mediated cross-coupling of iodoarenes and perfluoroalkyl iodides is supposed to be similar to that of related reactions involving the interaction of halogenoarenes with cuprous salts of organic nucleophilic anions (for example CuCN) [55] (Scheme 2.122). First a solvated perfluoroalkyl copper(I) complex is formed. This then coordinates to the iodoarene followed by exchange of ligands [56]. Several electron-transfer steps are probably involved in this process. 

Convenient reagents for incorporation of perfluoroalkyl groups in a molecule of pyridine are 1,10-phenanthroline-ligated (perfluoroalkyl) copper (I) complexes 274 [166], which were obtained by reaction of copper 1,10-phenanthroline complex with Ruppert reagent and its CaFs-analog. The 1,10-phenanthroline complex (274a) has been used in reaction with 3-iodopyridine (273) for synthesis 3-trifluoromethylpyridine (275) [167, 168] (Scheme 81). 

The more general approach to fluoroalkylthiophenes is anionic perfluoroalkylation of 2-bromthiophenes with perfluoroalkyliodides in the presence of copper." " The mechanism of perfluoroalkylation reaction consists of the steps involving the formation of solvated complex of fluoroaUcylcopper, coordination of heterocyclic halide and ligands exchange at copper center. ... 

Perfluoroalkylcopper compounds, derived from perfluoroalkyl halides and copper in dipolar aprotic solvents such as dimethyl sulfoxide and N,N-dimethylacetamide, are rather stable. These complexes couple effectively with aryl and vinyl halides (Burdon et al., 1967, 1972a McLoughlin and Thrower, 1969). 

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