A formal synthesis of (−)‐rotundone

Abstract (−)‐Rotundone, an oxygenated sesquiterpene noted for intense woody and agarwood‐like aromas, is a key odorant in perfumery and flavor chemistry. Its remarkable potency has attracted synthetic interest, yet most reported approaches rely on guaiene‐type precursors, where difficult‐to‐separate off‐notes and poor oxidation selectivity complicate efficient access. Here, we report an alternative route from commercially available (+)‐( R )‐limonene that improves step economy and yield through a modified ring‐expansion step. This strategy enables direct construction of a cycloheptanone framework en route to the key Nazarov precursor to (−)‐rotundone in seven steps with 13% overall yield.