A concise synthetic method towards (-)-swainsonine and its 8-epimer by using palladium-catalyzed asymmetric hydroamination of alkoxyallene as the key strategy

Abstract

A concise and flexible formal synthesis of (-)-swainsonine and the 8-epimer is reported. The synthesis features sequential Pd-catalyzed asymmetric hydroamination of alkoxyallene and the Ru-catalyzed ring-closing-metathesis as the key strategy, which generates cyclic allylic N,O-acetal as the pivotal intermediate. Notably, this reaction could be performed on a multigram-scale. In addition, both the natural product and its 8-epimer could be obtained with comparable synthetic efficiency. (C) 2015 Elsevier Ltd. All rights reserved.