Ir-Catalyzed Cascade Reaction Promotes the Formation of Geometrically Selective Enones from Bis-allyl Alcohols

Enone compounds are well-known as useful building blocks that can be converted into a variety of valuable compounds. This study describes a synthetic method to synthesize E-selective or multi-substituted enones by an Ir-catalyzed cascade reaction under reducing conditions. We found that the cascade reaction, including reduction/isomerization/dehydration, proceeds by treating bis-allyl alcohol with Crabtree's catalyst in a hydrogen atmosphere, which forms the desired product with high diastereoselectivity. We investigated acceptable catalysts to the reaction and the synthesis of enone using di-, tri- and tetrasubstituted olefin substrates. Additionally, the given results suggested a hypothesis of reaction mechanism.