Vinyl Derivatives of Metals. XI. Reaction of Nucleophilic Reagents with Triethylperfluorovinylsilane

A Novel Stereospecific Route to (E)- and (Z)-(2-Substituted-1,2-difluoroethenyl)stannanes

“…The methodology for preparation of ( E )- and ( Z )-(2-substituted-1,2-difluoroethenyl)silanes, R‘CFCFSiR 3 (where R‘ = alkyl, aryl, H, I, etc. ), has been well established (Scheme ). − The key intermediate, (trifluorovinyl)triethylsilane (CF 2  CFSiEt 3 ), was prepared utilizing MeLi (ether solution), bromotrifluoroethylene, and chlorotriethylsilane in ether 13 or n -BuLi (hexane solution), chlorotrifluoroethylene, and chlorotriethylsilane in THF . Treatment of CF 2  CFSiEt 3 with LiAlH 4 in tetrahydrofuran resulted in the ( Z )-(1,2-difluorovinyl)triethylsilane ( trans -HCFCFSiEt 3 ) as the predominant isomer ( Z : E = 95:5 by 19 F NMR analysis), , which underwent isomerization easily with ultraviolet light (254 nm) and catalytic phenyl disulfide to afford the corresponding ( E ) isomer ( Z : E = 5:95) in high yield …”

“…( Z )-(2-Alkyl- or (2-aryl-1,2-difluoroethenyl)silanes ( trans ) were prepared through an addition−elimination reaction of (trifluorovinyl)silane with alkyl or aryl lithium reagents via a modified literature procedure (Scheme ). , Chlorotrimethylsilane was used in situ to trap the unstable CF 2 CFLi. It should be noted that compound 12 was obtained in better yield (75%) in ethyl ether than THF (41%), and ether could only be used for preparation of the volatile compound 8 (bp 95 °C).…”

Reactions of organotin compounds. VIII. The reactions of tin hydrides with perfluorovinyl silicon compounds

“…Addition reactions of perfluorovinylsilanes are also known, although frequently the elimination of a fluoride occurs readily. Thus triphenylsilyllithium adds to (C,H,),SiCF= CF, and the resulting adduct loses lithium fluoride (10).…”

Organometallic Compounds

“…Not surprisingly, trifluorovinyl groups are cleaved by aqueous potassium hydroxide from, for example, ðCF 2 5CFÞ 4 Si, Et 2 SiðCF5CF 2 Þ 2 and Et 3 SiCF5CF 2 , which may be obtained by the Grignard or lithium routes [100][101][102][103][104] (Figure 10.47).…”

“…However, with other nucleophiles attack also occurs at carbon in 10.48A, leading to displacement of fluorine [102] (Figure 10.48). (R S1 S)/(R S1 R) Yield Some syntheses of perfluoroalkyl and polyfluoroalkyl derivatives are shown in Figure 10.49.…”