We applied a highly convergent strategy based on our lead-optimization program that offered good flexibility for introducing structural modifications at nearly every position of the 16-membered-ring skeleton. This strategy is reflected in our synthetic route to ZK-EPO (Scheme 2) where we applied a Wittig reaction to connect C12 and C13, an aldol reaction [10, 11] to establish stereocenters C6 and C7, and finally a Yamaguchi cyclization for ...