Regio- and stereoselective synthesis of 1,4-dienes

Titanocene(II)-promoted cross-coupling between (Z)-alkenyl methyl sulfones and terminal allenes produced 1,4-dienes regioselectively via the formation of 2-alkylidenetitanacyclopentanes. Preferential formation of E,Z-dienes was observed in the reaction using aryl-, amino-, and phosphinylallenes.