Total Synthesis of (-)-Xishacorene B from ( R)-Carvone Using a C-C Activation Strategy.

The activation of C-C bonds that are traditionally viewed as unreactive, when coupled with other bond-forming processes, can offer new approaches to the synthesis of complex molecular scaffolds. In this Communication, we demonstrate the conversion of carvone to unusual bicyclo[3.3.1] and [3.2.1] frameworks by exploiting a Pd(0)-catalyzed C-C bond activation reaction and a radical cyclization process. This sequence is applied to a 10-step synthesis of the diterpene xishacorene B.