Further Insights into the Stereoselective Total Synthesis of Ageliferin via Dearomatizing Diels–Alder Cycloaddition

We report the total synthesis of ageliferin, focusing on the preparation of substrate for the D-tartrate-tethered cycloaddition and late-stage transformations. A D-tartrate-derived tether was designed to facilitate a challenging intramolecular dearomative Diels-Alder reaction of the hymenidin-derived units. The key cycloaddition proceeded with complete diastereoselectivity to construct the highly functionalized six-membered framework bearing three contiguous stereocenters. Conversion of the cycloadduct to ageliferin required careful adjustment of the reaction sequence, including protecting-group manipulations, introduction of azido groups onto the imidazole rings, cleavage of the N-N bond, and installation of the pyrrole-2-carbonyl units.