Perfluoroalkyl trimethylsilane

Reactions of polyfluoroalkylchromones with (perfluoroalkyl)trimethylsilanes proceed as a 1,4-nucleophilic per-fluoroalkylation to give 2,2-bis(polyfluoroalkyl)chroman-4-ones with high regioselectivity and good yield after acid hydrolysis of trimethylsilyl (TMS) ethers (e.g., see Scheme 52) <2003JOC7747>. 

Perfluoroalkyl-chroman-4-ones react with (perfluoroalkyl)trimethylsilane in the presence of a catalytic amount of tetra- -butyl ammonium fluoride (TBAF) to give 2-bis(perfluoroalkyl)-277-chromenes 75 as the major products along with trace amounts of the corresponding 477-chromenes 76 (Equation 41) <2003TL2097>. 

Trifluoromethylation (perfluoroalkylation) by reaction of carbonyl compounds with (trifluoromethyl)trimethylsilane or (perfluoroalkyl)trimethylsilane. 

Nucleophilic Perfluoroalkylation of Nitrones The reaction of a,N-diaryl nitrones with (trifluoromethyl)trimethylsilane (TMSCF3) gives O-trimethylsilyl ethers of a-(trifluoromethyl)-hydroxylamines. This reaction is initiated by potassium ten -butoxide. Removal of the trimethylsilyl group on acid treatment leads to a-(trifluoromethyl)hydroxylamines, whereas catalytic hydrogenation gives a-(trifluoromethyl)amines (Scheme 2.194). 

High molecular weight perfluorinated tertiary alcohols can be prepared by the reaction of (perfluoroalkyl)- and (perfluorooxaalkyl)trimethylsilanes with fluoro ketones (vide supra). The reaction has been extended to carbonyl compounds other than ketones acid fluorides gave ketones, but no reaction was observed with esters. a-Oxo esters react with trimethyl(tri-fluoromcthyl)silane with fluoride initiation in tetrahydrofuran /(./(. -trifluoro lactic acid derivatives are produced in good yields in one step. 

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