Synthesis of Tanshinone IIA and Related Terpenes via a C-H Functionalization Strategy.

The total synthesis of tanshinone IIA and related bioactive diterpenes isolated from the Chinese plant Salvia miltiorrhiza was completed from a common tetralin building block. The synthetic route highlights a 3,4-disubstituted furan synthesis and various regioselective C-H functionalization reactions, including a Pd catalyzed iodination and an Ir catalyzed borylation, along with an intramolecular stanna-Brook type reaction to construct the ortho -quninone ring of the target molecule.