Total syntheses of (-)-haemanthidine, (+)-pretazettine, and (+)-tazettine.
[structures: see text] The total syntheses of the amaryllidaceae alkaloids haemanthidine, pretazettine, and tazettine as optically pure enantiomers are reported. Using D-mannose as the starting material, the critical relative stereochemical relationships are established with an intramolecular nitrone-alkene cycloaddition reaction. The synthetic route leads successively to (-)-haemanthidine and then to (+)-pretazettine and (+)-tazettine, taking advantage of the well-established complex relationships among these three alkaloids.
Baldwin
S W
SW
Department of Chemistry, Duke University, Durham, North Carolina 27708, USA. baldwin@chem.duke.edu
Debenham
J S
JS
D000470:Alkaloids / Q000138:chemical synthesis*; D047151:Amaryllidaceae Alkaloids; D000972:Antineoplastic Agents, Phytogenic / Q000138:chemical synthesis*; D010617:Phenanthridines; D010936:Plant Extracts / Q000138:chemical synthesis; D013237:Stereoisomerism
D000470:Alkaloids; D047151:Amaryllidaceae Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D010617:Phenanthridines; D010936:Plant Extracts; C010766:pretazettine; C083906:hemanthidine; C011361:tazettine