Proof of the Absolute Configuration of (-)-(S)-2-hydroxy-β-ionone by Correlation with Ursolic Acid with (-)-trans-Verbenol

Article abstract of DOI:10.1002/hlca.19810640402

(-)-(S)-2-Hydroxy-β-ionone (33), (+)-(2S,6S)-2-hydroxy-α-ionone (34), and their acetates 35 and 36 have been synthesized from (+)-(S)-6-methylbicyclo<4.3.0>non-1-ene-3,7-dione (3).The key intermediate (+)-(1R,3S,6S)-2,2,6-trimethyl-7-oxobicyclo<4.3.0>non-3-yl acetate (7) was correlated with a degradation product of the pentacyclic triterpene ursolic acid (16).Compound 33 was also synthesized by an alternative route starting from (-)-trans-verbenol (42).