Herein, we report the first asymmetric total synthesis of iheyamine B from 2,2'-bisindoloazepinone using the stereoselective construction of the trans-vicinal 2-oxopropyl moiety in the azepine scaffold. The asymmetric decarboxylative allylic alkylation provided the α-allylated 2,2'-bisindoloazepinone intermediate. The subsequent conversion of the lactam moiety into another allyl group in a trans-selective manner followed by Wacker oxidation of each allyl unit to the corresponding 2-oxopropyl group completed the total synthesis of iheyamine B.