N-Vinylpyridinium tetrafluoroborate salts as reagents for the stereoselective and regioselective synthesis of symmetrical (2E,4E)-1,6-dioxo-2,4-dienes

A general regioselective and stereoselective Pd(0)-catalyzed synthesis of substituted symmetrical (2E,4E)-1,6-dioxo-2,4-dienes is reported.