title: Flexible strategy for the synthesis of pyrrolizidine alkaloids.
abstract: A general strategy for the production of pyrrolizidine alkaloids is described, starting from intermediate (+)-9. The key features are diastereoselective dihydroxylation, inversion at the ring junction by hydroboration of an enamine, and ring closure to form the bicyclo ring system. This route is attractive because of its brevity and versatility; four natural products were prepared with differing stereochemistry and substitution patterns. Finally, this work allowed assignment of the absolute stereochemistry of 2,3,7-triepiaustraline and hyacinthacine A 7.
authors.affiliation: Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, United Kingdom. timothy.donohoe@chem.ox.ac.uk
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Donohoe
authors.forename: Rhian E
authors.initials: RE
authors.lastname: Thomas
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Cheeseman
authors.forename: Caroline L
authors.initials: CL
authors.lastname: Rigby
authors.forename: Gurdip
authors.initials: G
authors.lastname: Bhalay
authors.forename: Ian D
authors.initials: ID
authors.lastname: Linney
mesh_terms: D000588:Amines / Q000737:chemistry; D006900:Hydroxylation; D015394:Molecular Structure; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000588:Amines; D011763:Pyrrolizidine Alkaloids; C508850:hyacinthacine A1