1.2- Dichloro-3,3,4,4-tetrafluorocyclobutene

Preparation from 1,2-dichloro-3,3,4,4-tetrafluorocyclobutene (Penninsular Chemical Research Company, Inc.).1... 

Silicon difluoride reacts with the fluoro-olefins CH2.CHF, CH2 CFMe, CHj CF2, and CF2 CHF by insertion into the C F bond. Free-radical additions of triethylsilane to 1,2-dichloro-tetrafluorocyclobutene, -hexa-fluorocyclopentene, and -octafluorocyclohexene, and of the silanes HSiCl2Ph. HSiClj, HSiClgMe, HSiClMcj, and HSiEtg to the same cyclo-butene and cyclopentene, and the corresponding monochloro-compounds, have been described (see p. 200). Addition is accompanied by reduction of chlorine. 

Sodium pentacarbonylmanganate(—i) displaces chlorine from 1,2-dichloro-tetrafluorocyclobutene, and fluorine from perfluororgrclopentene, to give (8) and (9a), respectively. 

The perfluorinated tetracyclic 1,4-dithiocin structure (262) was assigned to a product obtained in low yield from the reaction of l,2-dichloro-3,3,4 4-tetrafluorocyclobutene with butyllithium and sulfur chloride (71TL2871). The product is a stable high melting solid. The 19F NMR chemical shifts very closely resemble those of dodecafluorotricyclobutabenzene, suggesting a ring current in (262). 

---