Enantioselective total synthesis of the reported structures of (-)-9-epi-presilphiperfolan-1-ol and (-)-presilphiperfolan-1-ol: Structural confirmation and reassignment and biosynthetic insights

Abstract

When epi isn't! The first total synthesis of the reported structures of 9-epi-presilphiperfolan-1-ol and presilphiperfolan-1-ol has been achieved. Key steps are a catalytic asymmetric alkylation of a novel diene-containing electrophile followed by a two-carbon ring contraction and an intramolecular Diels-Alder cycloaddition to form the stereochemically dense tricyclic core. The synthetic work has resulted in the structural revision of presilphiperfolan-1- ol (see scheme). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.