A Second-Generation Synthesis of the Cyanthiwigin Natural Product Core.

An improved synthesis of the cyanthiwigin natural product core enabled by new catalytic technology is reported. The key double catalytic enantioselective alkylation has been reoptimized using a recently developed protocol employing low loadings of palladium catalyst, thereby facilitating large-scale production of the tricyclic cyanthiwigin framework. Additionally, preparation of the penultimate aldehyde intermediate is expedited through the application of anti-Markovnikov Tsuji-Wacker oxidation.