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The highly reactive 14e species of “Cp2Ti(Ⅱ)”has emerged rapidly in the last decades[1],which has acted as the effective intermediate to promote the reductive coupling of unsaturated molecules.In addition,allene,1,2-propadiene,has attached much attention as a three-carbon unit and shown unique reactivity in numerous protocols addressed by transition metals,which cannot be realized simply by alkenes.In our research,Cp2TiEt2,acting as 14e species of “Cp2Ti(Ⅱ)”,could promote the reductive coupling of two molecules of allene to provide the a-a-bismethylenyltitanacyclopentane 1 in specific regio-and stereoselectivity,in which the configuration of the exocyclic double bonds were controlled as containing both substitutional groups of phenyl and alkyl,respectively.Although the skeleton of 1 is symmetric,the two Csp2-Ti bonds could be cleaved selectively and stepwisely via electrophilic substitution of halogenation reagents(such as NBS and NCS).2,5-asymmetricly functionalized 1,5-hexadiene derivatives 2 would be obtained in good yields,which could be involved in the synthesis of polysubstited olefin molecules or skeletons in some functional products.Therefore,we have demonstrated the efficient generation of 2,5-asymmetricly functionalized 1,5-hexadiene derivatives which could provide new methodologies of the corresponding organic compounds.