Asymmetric synthesis of stagonolide-D and stagonolide-G

Abstract

First asymmetric synthesis of the naturally occurring epoxy noneolide stagonolide-D has been reported in this article. Ring-closing metathesis (RCM) by Grubbs second generation catalyst, Sharpless asymmetric epoxidation (SAE), and cis-selective HornerWadsworthEmmons (HWE) olefination by Ando method are the key reactions successfully employed to achieve the target molecule in a divergent approach. Structurally related small ring macrolide stagonolide-G has also been synthesized by employing RCM and a metalenzyme combined dynamic kinetic resolution (DKR) strategy starting from (S)-ethyl lactate as a chiral pool. © 2011 The Chemical Society of Japan.