1-Lithio-2-bromotetrafluorobenzene reacts with sulphurdichloride, diphenylgermanium dichloride and mercuric chloride to give bis(2-bromotetrafluorophenyl) derivatives. The reactions of these derivatives with n-butyllithium and the subsequent synthesis of several heterocyclic compounds are described.
ophenyl-lithium react with sulphur dichloride, in ether-hexane, to give the corresponding aryl sulphides; various polyfluoroaryl sulphides are reported, including the new heterocycle octafluorothianthren. Reaction of the lithium reagents with sulphur monochloride or with organic disulphides leads to SS bond cleavage; and a nucleophilic displacement of CF−3 fromsulphur is reported. Cleavage of pentafluorophenyl-
Octaflurodibenzothiophen is synthesized by Ullmann coupling of bis(o-bromotetrafluorophenyl) sulphide and is shown to udergo nucleophilic substitution in the 2-position by methoxide ion. Similarly, substitution in octafluorothianthren occurs in the 2-position. The orientation of substitution in octafluorodibenzothiophen was deduced from the NMR spectra of the products and of the biphenyls which are