Alkyl fluorosilane

Oxidation of alkyl fluorosilanes to the corresponding alcohols. A variant of the Fleming-Kumada oxidation. 

The proposed intermediate is the pentacoordinate silyl radical, which eliminates the most stable alkyl radical to give the corresponding fluorosilane (equation 1 and Table 2). 

An in stereoisomer of fluorosilaphane 260 was obtained as depicted in Scheme 44 in overall 0.4% yield. First, tri(o-tolyl)fluorosilane 258 was fluorinated at silicon with AgF and then brominated with NBS to give tris[2-(bromomethyl)phenyl]fluorosilane 259. Condensation of 259 with l,3,5-tris(mercaptomethyl)benzene yielded the final product 260 <1998JA6421, 1999JOC5626>. The inside location of the fluorine atom was established by X-ray crystallographic analysis. The Si-F bond distance is very short (1.591 A) compared to the mean Si-F distance for all tetracoordinate tris[(alkyl(aryl)]fluorosilanes found in the Cambridge Structural Database. The 19F NMR resonance for 260 appears at a = 5.3 ppm, that is, 155 ppm upfield from that of tri(o-tolyl)fluorosilane 258. 

Anodic oxidation of tetraalkylsilanes in the presence of fluoride ions provides the corresponding fluorosilanes derived from cleavage of the C-Si bond, as in Eq. (20) [54]. The proposed intermediates are the pentacoordinate silyl radicals, which eliminate the most stable alkyl radical to give the corresponding fluorosilane. Becker and Shakkour found that anodic oxidation of cyclic peralkylsilanes results in the formation of a, )-difluorosi-lanes via Si-Si bond cleavage, as in Eq, (21) [55]. 

Numerous reports highlighting several permutations of the fluorosilane crosscoupling with aryl, alkenyl, and even alkyl halides were published in the following years after these initial developments [22]. As shown in Chart 7.1, this body of... 

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