Transition-metal-catalyzed cross-coupling through C H bond activation is emerging as one of the most important tools for carbon–carbon bond formation. In general, vinylogous compounds can be synthesized by Wittig, Heck, and Suzuki reactions, from the condensation of carbonyl compounds, C H addition to alkynes, or by means of organometallic alkenyl compounds, but direct alkenylation using C H bond activation remains particularly attractive for constructing carbon–carbon double bonds owing to their synthetic simplicity and use of readily available reagents. Vinylborates, vinyl halides, alkenyl acetates, and cyclic 1,3-dicarbonyls have been known for the direct alkenylation of arene and (hetero)arene C H bonds. In a more simple and synthetically useful alkenylation, terminal alkenes have been applied as the coupling partners. However, little attention has been paid to the direct alkenylation of alkenyl C H bonds with an alkene as the coupling partner using C H bond activation. 1,3-Butadienes, as a class of versatile organic synthetic reagents, have usually been prepared by indirect methods. To date, only two reports have been documented for their direct synthesis, involving coupling two simple terminal alkenes, owing to the difficulty in activating two alkene substrates at the same time (Scheme 1). Although two examples involving the reaction of 3-methyl-1H-indenes with tert-butyl acrylate were also reported, no work has been directed to the direct alkenylation of open-chain internal alkenes with another alkene as the coupling partner. In order to realize the direct cross-coupling of an internal alkene with a terminal alkene, the low reactivity of an internal alkenyl C H bond should be overcome. We envisioned the introduction of a structural element that could increase the reactivity of an internal alkenyl C H bond. Thus, we hypothesized that a 1,2-dithiane group at the terminal position of an alkene should satisfy the requirement on activating an internal alkenyl C H bond, and a-oxoketene dithioacetals were chosen as the internal alkenes. Herein, we report the palladium(II)-catalyzed direct cross-coupling of a-oxoketene dithioacetals with terminal alkenes as well as the synthesis of bicyclic pyridones [Eq. (1)].