A general synthetic route towards bastadins. Part 2: Synthesis of the western part of bastadins 4-16, and fully functionalized macrocycle of bastadin 12

Article abstract of DOI:10.1016/S0040-4039(99)01430-6

A general synthetic route for the construction of the western part of the macrocyclic bastadins 4-16 is presented. The western and the eastern segments were coupled using the imidazolide of the corresponding acid. The bromine at position Y² may be added at this advanced step regiospecifically, strengthening the convergence of the presented approach. Finally, the fully functionalized α,ω-aminoacid is cyclized with EDC affording the macrocyclic ring of bastadin-12 in 72% yield (3.5% overall yield).