Synthesis of butadiene-based sequence-controlled copolymers that are composed of commercial monomers such as styrene, butadiene, and ethylene was investigated. New substituted cyclododecadiene derivatives, 9-phenyl-1,5-cyclododecadiene was synthesized by reductive-phenylation method from 1,5-cyclododecadiene-9-one and was polymerized with tungsten-based catalyst systems to obtain a microstructure-controlled terpolymer. A sequence-controlled 2 : 1 : 1 terpolymer of butadiene, styrene and ethylene was successfully synthesized. The glass transition of the terpolymer occurred at -33.6 degrees C.