Synthesis of the Cytotrienin A CoreviaMetal Catalyzed C−C Coupling
摘要:
A synthetic approach to the C17-benzene ansamycins via metal catalyzed C-C coupling is described. Key bond formations include direct iridium catalyzed carbonyl crotylation from the alcohol oxidation level followed by chelation-controlled Sakurai-Seyferth dienylation to form the stereotriad, which Is attached to the arene via Suzuki cross-coupling. The diene-containing carboxylic acid is prepared using rhodium catalyzed acetylene-aldehyde reductive C-C coupling mediated by gaseous hydrogen. Finally, ring-closing metathesis delivers the cytotrienin core.