Cytotoxic alkaloids motuporamines A-C: Synthesis and structural verification

[GRAPHICS] The unusual structure and biological properties of the marine alkaloids mot uporamines A-C, as well as the uncertainty as to the position of the olefin within the ring of motuporamine C, led us to synthesize these compounds. T he strategy utilized the ring closing metathesis reaction to form the 14- a nd 15-membered rings and Michael addition and amidation chemistry to introd uce the spermine-like unit, The syntheses, structure assignment verificatio ns, and also the determination of the position of the olefin in motuporamin e C are described.