title: Racemization-free synthesis of (S)-(+)-tylophorine from L-proline by radical cyclization.
abstract: The phenanthroindolizidine alkaloid (S)-(+)-tylophorine was synthesized from L-proline in nine linear steps including a double bromination and a free-radical cyclization of an N-aziridinylimine as the key steps. The phenanthrene moiety was prepared from homoveratric acid and veratraldehyde and permits the variation of each oxygen-substituted ring.
authors.affiliation: Department of Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Stoye
authors.forename: Till
authors.initials: T
authors.lastname: Opatz
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis*; D003500:Cyclization; D007212:Indolizines / Q000138:chemical synthesis*; D010616:Phenanthrenes / Q000138:chemical synthesis*; D011392:Proline / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D007212:Indolizines; D010616:Phenanthrenes; D011392:Proline; C004218:tylophorine