Novel synthesis of the 2-azaanthraquinone alkaloid, scorpinone, based on two microwave-assisted pericyclic reactions

The total synthesis of the 2-azaanthraquinone alkaloid, scorpinone ( 4), isolated from the mycelium of a Bispora-like tropical fungus, has been completed in nine steps. The two key steps involve a microwave-assisted thermal electrocyclic reaction for the synthesis of an 8-oxygenated isoquinoline skeleton from a 1-aza 6π-hexatriene system, and a regioselective microwave-assisted [4+2] cycloaddition for the construction of a 2-azaanthraquinone framework.