Asymmetric Total Synthesis of Glabridin

Glabridin, a biologically important prenylated isoflavone, remains a persistent challenge for its efficient and stereoselective synthesis. We herein describe a novel asymmetric total synthesis of this natural product. The route commenced with the independent preparation of A-ring precursor a and B/C-ring fragment b. Glabridin was subsequently obtained in 99.9% ee over a concise six-step sequence, achieving an overall yield of 19%. The synthesis features several pivotal transformations: a Mitsunobu reaction to couple the key fragments; a hydroxy-iodination followed by a one-pot, intramolecular Friedel-Crafts alkylation and oxidation to efficiently assemble the tetracyclic core; and a final mild demethylation catalyzed by tris(pentafluorophenyl)borane. This route proceeds under mild conditions with excellent selectivity, offering a practical strategy for accessing Glabridin.