Total synthesis of cyanthiwigins A, C, G, and H.

The first total synthesis of cyanthiwigins A, C, H and concise synthesis of cyanthiwigin G was achieved from a common intermediate. A modified formal [4 + 2] cycloaddition was developed to construct the key cis-hydrindanone (A-B). Stereospecific 1,4-addition, alkylation, and ring-closing metathesis were used to build the tricarbocyclic ring system (A-B-C). Various site-selective oxidations were applied to create the desired oxidation states of the different cyanthiwigins.