Fluorinated butatrienes

Major improvements in the synthesis of 1,1,4,4-tetrafluorobutatriene (1) are presented. Despite many attempts to isolate new metal complexes of 1 only an iron complex containing a ligand which is composed of a partially hydrolyzed tetrafluorobutatriene-dimer and carbon monoxide could be isolated and characterized by X-ray crystallography. Certain metal centers and solvents accelerate the decomposition of 1. First attempts to synthesize 1,1-difluorobutatriene (2) are presented which underline the major challenges of a successful synthesis of 2.