A Conia-Ene-Type Cyclization under Basic Conditions Enables an Efficient Synthesis of (-)-Lycoposerramine R

Abstract

An enantioselective total synthesis of the Lycopodium alkaloid lycoposerramine R is presented. It relies on a base-mediated cyclization that resembles the Conia-ene reaction of ynones and gold-catalyzed variants thereof. Thus, hydrindanones and other functionalized ring systems bearing an exocyclic alkene can be rapidly accessed at room temperature without noble metal catalysis or substrate preactivation.

Keywords: Conia-ene reaction; alkynes; hydrindanes; lycopodium alkaloids; total synthesis.