Protecting-group-free total synthesis of (E)- and (Z)-alstoscholarine

Abstract

Looking for hidden symmetry: The first asymmetric total synthesis of pentacyclic compounds 1 and 2 has been accomplished starting from a cyclic meso-anhydride. The absolute configuration of the final products was set by an organocatalytic desymmetrization of the meso-anhydride. The economic synthesis is protecting-group-free and confirms the assigned absolute configuration. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.