Total Synthesis of (−)-Flueggeacosine C

Abstract

Herein we describe a total synthesis of the heterodimeric securinega alkaloid (−)-flueggeacosine C (8). The convergent synthetic strategy is based on a Liebeskind−Srogl cross-coupling reaction that combines a benzoquinolizidine fragment with a securinine-type alkaloid. An acyloxy nitroso ring-expansion was employed as the key step in accessing benzoquinolizidine 9, and a novel intramolecular Diels−Alder reaction of an allenic acid-containing pyridone expeditiously delivers the skeleton of the securinine-type fragment ( 16). Finally, a Cu-catalyzed hydroboration-oxidation sequence was employed to regio-and diastereoselectively introduce the secondary alcohol found in 8.