Flexible strategy for the synthesis of pyrrolizidine alkaloids.
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.
Donohoe
Timothy J
TJ
Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, United Kingdom. timothy.donohoe@chem.ox.ac.uk
Thomas
Rhian E
RE
Cheeseman
Matthew D
MD
Rigby
Caroline L
CL
Bhalay
Gurdip
G
Linney
Ian D
ID
D000588:Amines / Q000737:chemistry; D006900:Hydroxylation; D015394:Molecular Structure; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D000588:Amines; D011763:Pyrrolizidine Alkaloids; C508850:hyacinthacine A1