title: Expedient pyrrolizidine synthesis by propargylsilane addition to N-acyliminium ions followed by gold-catalyzed alpha-allenyl amide cyclization.
abstract: A reaction sequence, involving the addition of (substituted) propargylsilanes to lactam-derived N-acyliminium ions followed by gold-catalyzed cyclization of the resulting alpha-allenyl amide, is applied in expedient syntheses of pyrrolizidine alkaloids heliotridine and ent-retronecine in five steps from (S)-malic acid.
authors.affiliation: Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands.
authors.forename: Arjen C
authors.initials: AC
authors.lastname: Breman
authors.forename: Jan
authors.initials: J
authors.lastname: Dijkink
authors.forename: Jan H
authors.initials: JH
authors.lastname: van Maarseveen
authors.forename: Sape S
authors.initials: SS
authors.lastname: Kinderman
authors.forename: Henk
authors.initials: H
authors.lastname: Hiemstra
mesh_terms: D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006046:Gold / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D007700:Kinetics; D007769:Lactams / Q000737:chemistry; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*
chemical_list: D000577:Amides; D007097:Imines; D007769:Lactams; D011763:Pyrrolizidine Alkaloids; D012821:Silanes; D006046:Gold