Asymmetric Total Synthesis of Pentacyclic Indole Alkaloid Andranginine and Absolute Configuration of Natural Product Isolated from Kopsia arborea

The first asymmetric total synthesis of andranginine (1) via an asymmetric Morita–Baylis–Hillman reaction and a diastereoselective intramolecular Diels–Alder reaction has revealed that natural andranginine (1) isolated from Kopsia arborea existed as a scalemic mixture and contained predominantly the (16R,21S) form rather than the (16S,21R) form.