A convergent Approach based on local symmetry en route to (-)-Callystatin

International audienceA convergent synthetic approach of the highly cytotoxic natural product (−)-callystatin A was developed assembling three fragments through Julia-Kocienski olefination and Stille cross-coupling. The new strategy relies on a pivotal local symmetry of the target molecule. In this preliminary study, particular attention was devoted to facilitate the catalytic enantiocontrol of strategic stereogenic centers present in each of the fragments