Total Synthesis of (?)-Isatisine A

摘要

A modular total synthesis of (−)-isatisine A isndescribed in which four consecutive metal-mediated transformationsnhave been employed at the final stage. These includen[Pd]-catalyzed Sonogashira coupling, [Pd]-catalyzed nitroalkynencycloisomerization leading to isatogens, and addition ofnindoles to isatogens using InCl3- and [Rh]-catalyzed oxidativenN-heterocyclization of amino alcohol to form the key amidenbond. In addition to these, the removal of the protecting groupsnhas also been carried out in a selective fashion employing eitherncatalytic or stoichiometric metal/metal-based reagents.