Grignard compounds, perfluoroalkylation

Perfluoroalkyl- and perfluoroaryltitanium compounds were prepared m situ via reaction of the corresponding Grignard reagents with chlorotris(diethyl-amido)titaniuin [2SS] Reaction of the titanium compounds with aldehydes resulted in fluoroalkylative amination [2SS] (equation 192)... 

The introduction of a polyfluorinated chain is not so easy as that of an alkyl chain. Transition metal catalyzed cross-coupling of Grignard reagents and organozinc compounds are inefficient in the synthesis of polyfluorinated 3-alkylthiophene. The copper-catalyzed perfluoroalkylation results in the formation of 2-and 3-substituted thiophenes, which are difficult to separate from each other. The reaction of fluorinated alkylmagnesium iodide with 3-formylthiophene, follwed by reduction with lithium aluminum hydride, gave (22) in an overall yield of 40% [27]. 

Howells, R.D. and Gilman, H. (1975) Thermal decomposition of some perfluoroalkyl Grignard reagents. Synthesis of trons-l-halo- and tra s-l-alkylperfluorovinyl compounds. 

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