Preparation of α,ω-bis(dimethylhydrosilyl)perfluorohexane

Perfluoroalkylation with Organosilicon Reagents

“…One of the most general methods for the preparation of organosilicon compounds is based on the reactions between silyl halides and organometallic reagents (such as derivatives of magnesium and lithium) . Following Gilman's studies, various perfluoroalkylated organosilanes are accessible using this methodology. , Notable exceptions are CF 3 -containing organosilanes whose inaccessibility is attributed to the kinetic lability of the CF 3 -organometallic precursors that readily decompose to give the corresponding carbene species along with the formation of strong metal−fluorine bonds …”

“…5 Following Gilman's studies, various perfluoroalkylated organosilanes are accessible using this methodology. 6,7 Notable exceptions are CF 3containing organosilanes whose inaccessibility is attributed to the kinetic lability of the CF 3 -organometallic precursors that readily decompose to give the corresponding carbene species along with the formation of strong metal-fluorine bonds. 8 Alternative methods have been developed in order to avoid this problem.…”

“…The long-chain perfluorinated organosilanes are readily accessible via Grignard or Barbier-type reactions between the corresponding perfluorinated halides and trimethylsilyl chloride following Gilman's studies. 4a,, Markedly, this method is not applicable to CF 3 halides due to the competition from α-elimination of the fluoride ion from the precursor organometallic species. On the other hand, the long-chain perfluoroalkylated organometallics are relatively stable which allows them to be efficiently trapped with halogenated silanes.…”

“…In these CF 2 XY derivatives the derived anions are stabilized by the electron-withdrawing substituents that reduce the possibility of unwanted R-elimination of the fluoride ion from the intermediate "CF 2 X -" species (eq 6). 38 (Difluoromethyl)phenyldimethylsilane (7) was prepared by Ojima et al via substitution of chlorine in chlorodifluoromethane by (phenyldimethylsilyl)lithium obtained from the phenyldimethylchlorosilane by metalation (Scheme 5). 39 It was found, that Nbromosuccinimide (NBS) readily brominates the C-H bond in 7 giving the bromodifluoromethylated derivative 8.…”