Palladium-catalyzed coupling of alkynes with unactivated alkenes in ionic liquids: a regio- and stereoselective synthesis of functionalized 1,6-dienes and their analogues.

A palladium-catalyzed regio- and stereoselective intermolecular tandem reaction of alkynes and unactivated 1,6-enols in ionic liquids is described, providing a practical, efficient, and versatile method for the synthesis of functionalized 1,6-dienes in moderate to good yields. The present reaction has high functional-group tolerance and gives products on a gram scale. Mechanistic studies indicate that the reaction might proceed via a chain-walking mechanism.