The synthetic protocols for symmetrical/unsymmetrical 3,6-disubstituted 1,1,2,2-tetrafluorocyclohexane molecules were successfully established for the first time. Some of thus obtained tetrafluorinated cyclohexanes underwent recrystallization to afford trans-configured products preferentially. One of the unsymmetrical trans-disubstituted tetrafluorocyclohexanes, trans-1-ethyl-2,2,3,3-tetrafluoro-4
Thermal dimerization of 2,2-difluoro enol silyl ethers led to 3,3,4,4-tetrafluorocyclobutanes. The [2+2] cycloaddition proceeded in a “head-to-head” fashion to afford the cyclobutanes containing the trans and cis stereoisomers. The cyclobutanes were transformed to tetrafluorocyclobutane-1,2-diols by desilylation.
Oxidative cross-coupling of alpha-aryl-beta,beta-difluoroenol silyl ethers with heteroaromatics in the presence of Cu(OTf)(2) in wet acetonitrile proceeds smoothly, affording heteroaryldifluoromethyl aryl ketones in 61-88% yields. Alcohols also react as nucleophiles under the same conditions to provide alkoxydifluoromethyl aryl ketones in 73-80% yields.
DORMIDONTOV, YU. P.;SHADRINA, L. P., ZH. ORGAN. XIMII, 1983, 19, N 2, 269-273