Stereodivergent Synthesis of Three Contiguous Stereogenic Centers by Cu/Ir-Catalyzed Borylallylation.

Polyfunctional compounds bearing multiple stereogenic centers are synthetically valuable and important for complex molecule preparation. Herein, a Cu/Ir-catalyzed borylallylation of electron deficient alkenes is presented. The reaction operates by the cooperative function of a chiral Cu-complex and a chiral Ir-complex to generate products with high levels of stereocontrol. The method also allows for the stereodivergent synthesis of acyclic products with control of three stereogenic centers. Importantly, the products contain C─B, ester, and alkene functionalities, which allows for a diverse range of products to be generated. Finally, the highly functional nature of the products has been exploited in an efficient formal synthesis of the complex natural product (+)-(β)-Lycorane.