Synthesis of Azadirachtin: A Long but Successful Journey

Abstract

22 Years in the making: Azadirachtin (1) was synthesized for the first time by a highly convergent approach, utilizing a Claisen rearrangement and a radical cyclization as key steps. End-game strategies relied on intermediate 2, which could be obtained by synthetic methods as well as by degradation of 1. Bn=benzyl, TBS=tert-butyldimethylsilyl.