anti-Carbopalladation Cascades of Internal Alkynes Terminated by Intermolecular Suzuki and Sonogashira Reactions

In this report, we describe Pd-catalyzed cascade reactions in which two internal alkynes undergo two trans-carbocarbonation reactions, leading to new carbon–carbon bonds across the emerging double bonds. The resulting vinyl Pd intermediate being obtained after two carbopalladations is involved in either terminating Suzuki or Sonogashira reactions leading to either highly substituted butadienes or hexadienynes. A variety of different precursors as well as boronic acids and alkynes, respectively, were employed, yielding a broad spectrum of the corresponding products in yields of up to 82%.