Synthesis of (1Z,3Z)-1,4-dibromobutadiene, (1Z,3Z)-1-bromo-4-lithiobutadiene and (1Z,3Z)-1,4-dilithiobutadiene; stucture of (1Z,3Z)-(η5-C5H5)Fe(CO)2CH=CHCH=CHBr

Article abstract of DOI:10.1016/0022-328X(88)80518-7

An expedient synthesis of previously unknown (1Z, 3Z)-1,4-dibromobutadiene is reported.When this dibromide is treated with s- or t-butyllithium, (1Z,3Z)-1-bromo-4-lithio-butadiene is generated.Treatment of the dibromide with four equivalents of t-butyllithium gives (1Z,3Z)-dilithiobutadiene.Reaction of (1Z,3Z)-1-bromo-4-lithiobutadiene with (η⁵-C5H5)Fe(CO)2I gives (1Z,3Z)-(η⁵-C5H5)Fe(CO)2CH=CHCH=CHBr.X-ray crystallographic analysis of this latter compound establishes the geometry about the bromobutadiene ligand.