A Concise Total Synthesis of Glycinoeclepin A

Here we report a concise and modular synthesis of the complex triterpenoid glycinoeclepin A, a picomolar hatching stimulus for the notorious pest soybean cyst nematode. The synthesis features the strategic use of a polyfunctional platform intermediate bearing an aldehyde, a vinyl triflate, and an exo-cyclic alkene─three functional groups with orthogonal reactivity. From here, a programmable Cr-mediated diastereoselective homoallenylation of aldehyde, followed by a Pd-catalyzed intramolecular oxygenative cyclization, efficiently forged the densely functionalized 5,6-fused core system. The oxa-bicyclic appendage was installed via an allyl phosphonate enabled coupling. The remaining alkene was selectively homologated via a hydroboration, Wittig reaction. Final oxidations completed the total synthesis of glycinoeclepin A. This concise route not only provides access to glycinoeclepin A and analogs for potential biological studies but also establishes a general platform for synthesizing architecturally complex polycyclic natural products.