A New C−F Bond-Cleavage Route for the Synthesis of Octafluoro[2.2]paracyclophane

Reductive modification of difluoromethylene moiety in pentafluoropropionyl group

“…It is suggested that 6 is produced by migration of trimethylsilyl group on ring opening of epoxide 5 initially formed in the oxidation step [29,30]. Following fluoride ion promoted desilylative-defluorination of 6 proceeded smoothly to provide a valuable 1,2-diketone 7 by the use of catalytic amount of fluoride ion (Scheme 3), which is recycled as demonstrated by several 1,2- [31], 1,4- [32] and 1,6-desilylative-defluorination reactions [33].…”

Synthesis of 3,3,4,4-tetrafluoro-1,2-bis(imino)cyclobutanes: A cyclic version of fluorinated α-diimines

“…A trifluoromethylated compound in which a CF 3 group is attached to the p-electron system is a suitable substrate for Mg-mediated defluorination. Upon treatment with metallic magnesium and chlorotrimethylsilane, trifluoromethyl ketones [13], trifluoroacetates [14], trifluoromethylated imines [15], and aromatics [16] underwent defluorinative silylation to afford the corresponding difluoro compounds in good yields. A Mg(0)/ Me 3 SiCl system was also found to be effective for double defluorinative silylation of fluorinated a-diimines.…”

Functionalized fluoroalkyl and alkenyl silanes: Preparations, reactions, and synthetic applications

“…Hexafluoro-p-xylene 133 is allowed to react with magnesium in DMF in the presence of TMSCl, affording 134 in 48% yield. Then, the difluorosilane 134 undergoes the fluoride ioncatalyzed desilylative defluorination (1,6-elimination) on heating in anisole in the presence of 5 mol% of CsF at 160 8C to be transformed into p-xylylene intermediate 135 (Scheme 32) [44]. The tetrafluoro-p-xylylene 135 dimerizes to octafluoro[2.2]paracyclophane 136 (AF4) (53% isolated yield), which is an excellent precursor of the insulating parylene polymer [45].…”