Preparation of E-(1,2-difluoro-1,2-ethenediyl)bis(tributylstannane)

Chlorotrifluoroethene is converted in situ to [F2CCFSiMe3]. The crude [F2CCFSiMe3] solution is reduced with lithium aluminum hydride to (HFCCFSiMe3), which (without isolation) is converted to (Z)-HFCCFSnBu3. Subsequent metallation and trapping of the vinyllithium reagent with Bu3SnCl gives (E)-Bu3SnCFCFSnBu3 in 73% overall yield. Only two isolation steps are required and the use of Me3SiCl and F2CCFCl provides a cheap, economical route to this useful synthon.