Anticancer agents, macrocycles

Yu, M. J., Kishi, Y, Littlefield, B. A. Discover of E7389, a fully synthetic macrocyclic ketone analog of halichondrin B. In Anticancer Agents from Natural Products (Cragg, G. M., Kingston, D. G. L, Newman, D. J., Eds). Taylor and Francis Boca Raton, FL, 2005, pp. 241-265. 

Similarly, the 18-membered macrocycle 14, which served as a precursor for the synthesis of a bioactive analog of the anticancer agent antimycin Aj, was quickly produced by domino self-metathesis/RCM from the threonine derivative 13 (Scheme 2.4) [5b]. The Zhan catalyst 5 was shown to be more effective for this key step than the Grubbs catalysts 1 or 2. 

Epothilone is a highly potent anticancer agent. In their synthesis of highly potent epothilone analogs [51], Altmaim and coworkers reported that alkene precursor 61 was stereoselectively epoxidized with ketone ent-42 to give compounds 62a,b (Scheme 3.22). It appears that the epoxidation is compatible with several functional groups such as the benzimidazole in 61, and the existing ketone in the macrocycle did not appear to interfere with the epoxidation [51, 52]. 

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