Expedient Synthesis of (+)-cis-(2R,3S)-3-Hydroxyproline and (-)-(1S,5S)-2-Oxa-6-azabicyclo octan-3-one (The Geissman-Waiss Lactone): Formal Enantioselective Syntheses of (-)-Retronecine and Related Pyrrolizidine Alkaloids

Article abstract of DOI:10.1039/c39880000509

Yeast reduction of the keto-proline (5) affords the hydroxyproline derivative (6) (diastereoisomeric excess > 99percent cis; enantiomeric excess, e.e., 80percent(; subsequent hydrolysis and crystallization gives (+)-cis-(2R,3S)-3-hydroxyproline (7) (93percent e.e.) which has been homologated to the bicyclic lactones (10) and (11), precursors of (-)-retronecine, (+)-platynecine, (-)-croalbinecine and related pyrrolizidines.

Full text of DOI:10.1039/c39880000509

View Article Online / Journal Homepage / Table of Contents for this issue

View Article Online