Workshops der aufstrebenden Stars in der organischen Chemie

Abstract

An advanced ABCD fragment (see picture) constructed on the way to the total synthesis of the potent antitumor agent (+)‐spongistatin 2 has also been used in a formal total synthesis of (+)‐spongistatin 1. In both cases the critical step was an acid‐mediated epimerization in the presence of Ca2+ ions to stabilize the axial–equitorial CD spiroketal.