Straightforward synthesis of (R)-(-)-kjellmanianone.
A direct route to enantiomerically pure (-)-kjellmanianone is reported. The synthesis involves a cerium-catalyzed alpha-hydroxylation and an enzyme-catalyzed procedure to resolve tertiary alcohols at key stages. The intermediate beta-oxo ester was alpha-hydroxylated to give good yields of racemic kjellmanianone. The resolution of the racemic material was achieved by enzymatic saponification, followed by a chemical decarboxylation sequence to give enantiopure (-)-kjellmanianone with 99 % ee. Bromination then afforded the (-)-bromo derivative, whose X-ray structure provided evidence for the R configuration of (-)-kjellmanianone.
Institut für Organische Chemie der Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany. jchr@po.uni-stuttgart.de
Jens
J
Christoffers
Thomas
T
Werner
Wolfgang
W
Frey
Angelika
A
Baro
D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000737:chemistry; D001952:Bridged-Ring Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D003517:Cyclopentanes / Q000138:chemical synthesis* / Q000737:chemistry; D044647:Sargassum / Q000737:chemistry; D013237:Stereoisomerism
C487776:(R)-(-)-kjellmanianone; D000900:Anti-Bacterial Agents; D001952:Bridged-Ring Compounds; D003517:Cyclopentanes