1,OMEGA-DI-H-PERCHLOROPOLYENES FROM TRANS-DICHLOROETHYLENE VIA OXIDATIVE COUPLING

A stereospecific synthesis of trans-1,ω-di-H-perchloro polyenes H2(CCl)n (n = 4, 6, 8, 12, and 16) from trans-dichloro ethylene by repeated oxidative couplings is reported. The dimerization entails a low-temperature metalation of chloro olefinic substrates to give stable trans-dichloro-vinyllithium compounds, which are coupled by excess FeCl3. Mixed dimerization products are available from lithium organyls of different chain lengths. An oxidative oligomerization has been realized by the both-end coupling of 1,ω-di-Li-organyls, the preparation of which is given. Physical properties of the polychloro-polyenes are described and the mechanism of their formation is discussed. © 1969.