Synthesis of (+)-Cyanthiwigin U

Significance

Cyanthiwigin U is a diterpenoid containing a cyclohepta[e]indene ring system. Several related cyanthins and diterpene compounds have been isolated from marine organisms and fungi. Biological activities of this class include stimulation of nerve growth factor and inhibition of Mycobacterium tuberculosis. This first total synthesis of Cyanthiwigin U confirms the absolute stereochemistry of the natural product.