The steric structure effect of 6,6-dialkylfulvenes in reaction with 1,4-dilithiobutene (L-A), 1,6-dilithiohexane (L-B), 1,4-dilithiobenzene (L-C) and 1,2,3,4-teoraphenyl-1,4-dilithio-1,8-butadiene (L-D) are studied. Dilithium reagents L-A and L-B adds on the exo-cyclic double bound on 6,6-dimethyl-, 6-methyl-6-ethyl-, 6-methyl-6-n-propylfulvenes and 6,6-pentamethylenefulvene. The a-hydrogen abstraction reaction takes place when dilithium reagent L-C reacts with 6,6-dimethyl-, 6-methyl-6-ethyl-, 6-methyl-6-n-butylfulvenes and 6,6-tetramethylene-, 6,6-pentamethylene-, 6,6-hexamethylenefulvenes, except that the 6-methyl-6-n-propylfulvene undergoes reductive coupling reaction. With larger steric dilithium reagent L-D 6-methyl-6-n-propyl-, 6,6-pentamethylenefulvenes give rise to a-hydrogen abstraction reaction. Besides, a series of methylene-bridged and alkenyl substituted titanocenes and zirconocenes derivatives are prepared

Key words: REACTION MECHANISM, METALLOCENES, TITANIUM COMPLEX, ADDITION REACTION, ZIRCONIUM COMPLEX