A cross-conjugated triene, trans-3-methylene-1,4-hexadiene, is accessible from the Grignard reagent of chloroprene and methyloxirane via 1-methyl-3-methylene-4-pentenyl tosylate. The diene-transmissive Diels–Alder reaction of the triene and the stepwise sequence of double Diels–Alder reaction of the tosylate are investigated. Stereo- and regioselectivity of these reactions in the presence or absence of Lewis acid catalyst are discussed.