Additive- and Ligand-Free Cross-Coupling Reactions between Alkenes and Alkynes by Iridium Catalysis

Although a range of transition-metal-catalyzed cross-coupling reactions of alkenes and alkynes have been developed to produce valuable conjugated dienes, extension of these reactions to iridium catalysis has yet to be demonstrated. The first iridium-catalyzed alkene-alkyne cross-coupling reactions have been realized under ligand- and additive-free conditions. A wide range of acrylamides and alkynes could be used as coupling partners, providing branched (Z,Z)-butadiene skeletons with excellent site- and stereoselectivities. The utility of this approach is also demonstrated by preparative-scale and C-H functionalization of perillic and artemisic amides.