Total syntheses of macrocyclic marine alkaloids, haliclamines A and B: A convenient and expeditious assembly of 3-substituted pyridine derivatives with different alkyl chains to the bispyridinium macrocycle

Article abstract of DOI:10.1016/S0040-4020(98)00752-2

The total syntheses of haliclamines A (1) and B (2), macrocyclic marine alkaloids closely related to the key bisdihydropyridine intermediate 3 of the biogenetically unique manzamine family, have efficiently been achieved via stepwise controlled inter- and intramolecular N-alkylations of 3- alkylpyridine derivatives such as 40 and 41. The general synthetic methodology toward the bispyridinium macrocycle 44, a key biogenetic equivalent of the polycyclic marine alkaloids, has been proposed through the total syntheses.