title: A synthesis of alsmaphorazine B demonstrates the chemical feasibility of a new biogenetic hypothesis.
abstract: An N-oxide fragmentation/hydroxylamine oxidation/intramolecular 1,3-dipolar cycloaddition cascade efficiently converted an oxidized congener of akuammicine into the complex, hexacyclic architecture of the alsmaphorazine alkaloids. This dramatic structural change shows the chemical feasibility of our novel proposal for alsmaphorazine biogenesis. Critical to these endeavors was a marked improvement in our previously reported Zincke aldehyde cycloaddition approach to indole alkaloids, which permitted the gram-scale synthesis of akuammicine. The chemoselective oxidations of akuammicine leading up to the key rearrangement also generated several biogenetically related alkaloids of the alstolucine and alpneumine families.
authors.affiliation: Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025, United States.
authors.forename: Allen Y
authors.initials: AY
authors.lastname: Hong
authors.affiliation: Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025, United States.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Vanderwal
mesh_terms: D003500:Cyclization; D026121:Indole Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D026121:Indole Alkaloids; C554257:alsmaphorazine B