A Short Synthesis of the Tricyclic Core Common to Lycopodine-Like Lycopodium Alkaloids: Discovery of a Separable Pair of Keto-Enol Tautomers

The effective synthesis of strained Lycopodium alkaloids bearing lycopodine-like frameworks, categorized as miscellaneous, continues to pose significant synthetic challenges. Herein, we outline a concise and scalable strategy for the construction of the ABC tricyclic core of this class of natural products, which is amenable to asymmetric synthesis. A tandem Michael–Claisen condensation enables rapid assembly of the core structure while offering prospects for derivatization. In the process, a pair of keto-enol tautomers that could be separated and characterized at room temperature was discovered.