“…Interestingly, excluding the synthetic compound eeyarestatin I, all the other Sec61α inhibitors belong to one of the distinct classes of macrocyclic natural products with different ring sizes: cotransins (21-membered), , apratoxins (25-membered), , mycolactone (12-membered), − decatransin (30-membered), coibamide A (22-membered), , and ipomoeassins (20-membered). , Thus, it appears that a macrocyclic ring is a preferred structural feature among Sec61α-targeting inhibitors. Furthermore, this variation in ring sizes between known inhibitors made us wonder whether the current ring size is already optimal for each macrocycle. , However, no such SAR explorations have been reported. To address how ring size may affect the biological activity of ipomoeassin F, one of the most potent Sec61 inhibitors identified to date, we designed two new analogues ( 1 and 2 , Figure ) with an 18-membered and 22-membered ring, respectively.…”