Regio- and Stereoselective Synthesis of Multisubstituted Olefins and Conjugate Dienes by Using α-Oxo Ketene Dithioacetals as the Building Blocks

An efficient palladium(0)-catalyzed, Cu(I)-mediated synthetic route to trisubstituted olefins and conjugate dienes has been developed via oxo directing Liebeskind-Srogl cross-coupling reactions of gem-dihaloolefin-type alpha-oxo ketene dithioacetals with aryl and alkenylboronic acids. The synthetic protocol has demonstrated rare examples of transition-metal-promoted transformations of ketene dithioacetals, providing a novel route to highly functionalized conjugate dienes.