Stereospecific preparation of symmetrical (1Z, 3Z)- and (1E, 3E)-2,3-difluoro-1,4-disubstituted-buta-1,3-dienes from 1-bromo-1-fluoroalkenes

A straightforward method to prepare symmetrical (1Z, 3Z) and (1E, 3E) 2,3-difluoro-1,4-disubstituted-buta-1,3-dienes from high E/Z ratio and (Z) 1-bromo-1-fluoroalkenes, respectively is described.