The first total synthesis of cerorubenic acid-III methyl ester is detailed. Enantiopure 4, obtained by anionic oxy-Cope rearrangement of 3, was transformed via diol 11 into lactol 20. Following proper establishment of both side chains as in 25, a 6-exo radical cyclization was employed to set the configuration of the remaining stereogenic centers. This very useful process set the stage for construction of the pendant side chain. The complete route to 2 from 3-methylcyclohexenone required 30 steps (0.3% overall yield) confirmed the initial complex structural assignment and established the absolute configuration of the natural kairomone.